Effect of the hard phase on the densification and properties of the hard materials composed of Al

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金属材料专业英语词汇

Material Science 材料科学Material Science Definition 材料科学定义Machinability[məʃi:nə'biliti]加工性能Strength .[streŋθ]强度Corrosion & resistance durability.[kə'rəʊʒən] &[ri'zistəns] .[ 'djʊrə'bɪlətɪ] 抗腐蚀及耐用Special metallic features 金属特性Allergic, re-cycling & environmental protection 抗敏感及环境保护Chemical element 化学元素Atom of Elements 元素的原子序数Atom and solid material 原子及固体物质Atom Constitutes 原子的组织图Periodic Table 周期表Atom Bonding 原子键结合Metal and Alloy 金属与合金Ferrous & Non Ferrous Metal 铁及非铁金属Features of Metal 金属的特性Crystal Pattern 晶体结构Crystal structure, Space lattice & Unit cell 晶体结构，定向格子及单位晶格X – ray crystal analytics method X线结晶分析法Metal space lattice 金属结晶格子Lattice constant 点阵常数Mill's Index 米勒指数Metal Phase and Phase Rule金相及相律Solid solution 固熔体Substitutional type solid solution 置换固熔体Interstitial solid solution 间隙固熔体Intermetallic compound 金属间化合物Transformation 转变Transformation Point 转变点Magnetic Transformation 磁性转变Allotropic Transformation 同素转变Thermal Equilibrium 热平衡Degree of freedom 自由度Critical temperature 临界温度Eutectic 共晶Peritectic [.peri’tekti k] Temperature包晶温度Peritectic Reaction 包晶反应Peritectic Alloy 包晶合金Hypoeutectic Alloy 亚共晶体Hypereutectic Alloy 过共晶体Plastic Deformation 金属塑性Slip Plan 滑动面Distortion 畸变Work Hardening 硬化Annealing 退火Crystal Recovery 回复柔软Recrystallization 再结晶Properties & testing of metal 金属材料的性能及试验Chemical Properties 化学性能Physical Properties 物理性能Magnetism 磁性Specific resistivity & specific resistance 比电阻Specific gravity & specific density比重Specific Heat比热热膨胀系数 Coefficient of thermal expansion导热度 Heat conductivity机械性能 Mechanical properties屈服强度(降伏强度) (Yield strength)弹性限度、杨氏弹性系数及屈服点 elastic limit, Young’s module of elasticity to yield point伸长度 Elongation断面缩率 Reduction of area破坏性检验 destructive inspections渗透探伤法 Penetrate inspection磁粉探伤法 Magnetic particle inspection放射线探伤法 Radiographic inspection超声波探伤法 Ultrasonic inspection显微观察法 Microscopic inspection破坏的检验 Destructive Inspection冲击测试 Impact Test疲劳测试 Fatigue Test蠕变试验Creep Test潜变强度 Creeps Strength第一潜变期 Primary Creep第二潜变期 Secondary Creep第三潜变期 Tertiary Creep主要金属元素之物理性质 Physical properties of major Metal Elements工业标准及规格–铁及非铁金属 Industrial Standard – Ferrous & Non – ferrous Metal磁力 Magnetic简介 General软磁 Soft Magnetic硬磁 Hard Magnetic磁场 Magnetic Field磁性感应 Magnetic Induction导磁率[系数,性] Magnetic Permeability磁化率 Magnetic Susceptibility (Xm)磁力(Magnetic Force)及磁场 (Magnetic Field)是因物料里的电子 (Electron)活动而产生抗磁体、顺磁体、铁磁体、反铁磁体及亚铁磁体 Diamagnetism, Paramagnetic, Ferromagnetisms, Antiferromagnetism & Ferrimagnetisms抗磁体 Diamagnetism磁偶极子 Dipole负磁力效应 Negative effect顺磁体 Paramagnetic正磁化率 Positive magnetic susceptibility铁磁体 Ferromagnetism转变元素 Transition element交换能量 Positive energy exchange外价电子 Outer valence electrons化学结合 Chemical bond自发上磁 Spontaneous magnetization磁畴 Magnetic domain相反旋转 Opposite span比较抗磁体、顺磁体及铁磁体 Comparison of Diamagnetism, Paramagnetic & Ferromagnetism反铁磁体 Antiferromagnetism亚铁磁体 Ferrimagnetism磁矩 magnetic moment净磁矩 Net magnetic moment钢铁的主要成份 The major element of steel钢铁用"碳"之含量来分类 Classification of Steel according to Carbon contents铁相 Steel Phases钢铁的名称 Name of steel铁素体Ferrite渗碳体 Cementitle奥氏体 Austenite珠光体及共析钢 Pearlite &Eutectoid奥氏体碳钢 Austenite Carbon Steel单相金属 Single Phase Metal共释变态 Eutectoid Transformation珠光体 Pearlite亚铁释体 Hyppo-Eutectoid初释纯铁体 Pro-entectoid ferrite过共释钢 Hype-eutectoid粗珠光体 Coarse pearlite中珠光体 Medium Pearlite幼珠光体 Fine pearlite磁性变态点 Magnetic Transformation钢铁的制造 Manufacturing of Steel连续铸造法 Continuous casting process电炉 Electric furnace均热炉 Soaking pit全静钢 Killed steel半静钢 Semi-killed steel沸腾钢(未净钢) Rimmed steel钢铁生产流程 Steel Production Flow Chart钢材的熔铸、锻造、挤压及延轧 The Casting, Fogging, Extrusion, Rolling & Steel熔铸 Casting锻造 Fogging挤压 Extrusion延轧Rolling冲剪 Drawing & stamping特殊钢以元素分类Classification of Special Steel according to Element特殊钢以用途来分类 Classification of Special Steel according to End Usage 易车(快削)不锈钢 Free Cutting Stainless Steel含铅易车钢 Leaded Free Cutting Steel含硫易车钢 Sulphuric Free Cutting Steel硬化性能 Hardenability钢的脆性 Brittleness of Steel低温脆性 Cold brittleness回火脆性 Temper brittleness日工标准下的特殊钢材 Specail Steel according to JIS Standard铬钢–日工标准 JIS G4104 Chrome steel to JIS G4104铬钼钢钢材–日工标准 G4105 62 Chrome Molybdenum steel to JIS G4105镍铬–日工标准 G4102 63 Chrome Nickel steel to JIS G4102镍铬钼钢–日工标准 G4103 64 Nickel, Chrome & Molybdenum Steel to JIS G4103高锰钢铸–日工标准 High manganese steel to JIS standard片及板材 Chapter Four-Strip, Steel & Plate冷辘低碳钢片(双单光片)(日工标准 JIS G3141) 73 - 95 Cold Rolled (Low carbon) Steel Strip (to JIS G 3141)简介 General美材试标准的冷辘低碳钢片 Cold Rolled Steel Strip American Standard – American Society for testing and materials (ASTM)日工标准 JIS G3141冷辘低碳钢片 (双单光片)的编号浅释 Decoding of cold rolled(Low carbon)steel strip JIS G3141材料的加工性能 Drawing ability硬度 Hardness表面处理 Surface finish冷辘钢捆片及张片制作流程图表 Production flow chart cold rolled steel coil sheet冷辘钢捆片及张片的电镀和印刷方法 Cold rolled steel coil & sheet electro-plating & painting method冷辘(低碳)钢片的分类用途、工业标准、品质、加热状态及硬度表 End usages, industrial standard, quality, condition and hardness of cold rolled steel strip硬度及拉力 Hardness & Tensile strength test拉伸测试(顺纹测试) Elongation test杯突测试(厚度: 0.4公厘至 1.6公厘，准确至 0.1公厘 3个试片平均数 ) Erichsen test (Thickness: 0.4mm to 1.6mm, figure round up to 0.1mm)曲面(假曲率) Camber厚度及阔度公差 Tolerance on Thickness & Width平坦度(阔度大于 500公厘，标准回火 ) Flatness (width>500mm, temper: standard)弯度 Camber冷辘钢片储存与处理提示 General advice on handling & storage of cold rolled steel coil & sheet 防止生锈 Rust Protection生锈速度表 Speed of rusting焊接 Welding气焊 Gas Welding埋弧焊 Submerged-arc Welding电阻焊 Resistance Welding冷辘钢片(拉力: 30-32公斤/平方米)在没有表面处理状态下的焊接状况 Spot welding conditions for bared (free from paint, oxides etc) Cold rolled mild steel sheets(T/S:30-32 Kgf/ µ m2)时间效应(老化)及拉伸应变 Aging & Stretcher Strains日工标准(JIS G3141)冷辘钢片化学成份 Chemical composition – cold rolled steel sheet to JIS G3141冷辘钢片的"理论重量"计算方程式 Cold Rolled Steel Sheet – Theoretical mass 日工标准(JIS G3141)冷辘钢片重量列表 Mass of Cold-Rolled Steel Sheet to JIS G3141冷辘钢片订货需知Ordering of cold rolled steel strip/sheet其它日工标准冷轧钢片(用途及编号) JIS standard & application of other cold Rolled Special Steel电镀锌钢片或电解钢片Electro-galvanized Steel Sheet/Electrolytic Zinc Coated Steel Sheet电解/电镀锌大大增强钢片的防锈能力Galvanic Action improving Weather & Corrosion Resistance of the Base Steel Sheet上漆能力 Paint Adhesion电镀锌钢片的焊接 Welding of Electro-galvanized steel sheet点焊 Spot welding滚焊 Seam welding电镀锌(电解)钢片 Electro-galvanized Steel Sheet生产流程 Production Flow Chart常用的镀锌钢片(电解片)的基层金属、用途、日工标准、美材标准及一般厚度 Base metal, application, JIS & ASTM standard, and Normal thickness of galvanized steel sheet锌镀层质量 Zinc Coating Mass表面处理 Surface Treatment冷轧钢片 Cold-Rolled Steel Sheet/Strip热轧钢片 Hot-Rolled Sheet/Strip电解冷轧钢片厚度公差 Thickness Tolerance of Electrolytic Cold-rolled sheet热轧钢片厚度公差 Thickness Tolerance of Hot-rolled sheet冷轧或热轧钢片阔度公差 Width Tolerance of Cold or Hot-rolled sheet长度公差 Length Tolerance理论质量 Theoretical Mass锌镀层质量(两个相同锌镀层厚度) Mass Calculation of coating (For equal coating)/MM锌镀层质量(两个不同锌镀层厚度) Mass Calculation of coating (For differential coating)/MM镀锡薄铁片(白铁皮/马口铁) (日工标准 JIS G3303)简介 General镀锡薄铁片的构造 Construction of Electrolytic Tinplate镀锡薄钢片(白铁皮/马日铁)制造过程 Production Process of Electrolytic Tinplate锡层质量 Mass of Tin Coating (JIS G3303-1987)两面均等锡层 Both Side Equally Coated Mass两面不均等锡层 Both Side Different Thickness Coated Mass级别、电镀方法、镀层质量及常用称号Grade, Plating type, Designation of Coating Mass & Common Coating Mass镀层质量标记 Markings & Designations of Differential Coatings硬度 Hardness单相轧压镀锡薄铁片(白铁皮/马口铁) Single-Reduced Tinplate双相辗压镀锡薄钢片(马口铁/白铁皮) Dual-Reduction Tinplate钢的种类 Type of Steel常用尺寸 Commonly Used Size电器用硅 [硅] 钢片 Electrical Steel Sheet简介 General软磁材料 Soft Magnetic Material滞后回线 Narrow Hysteresis矫顽磁力 Coercive Force硬磁材料 Hard Magnetic Material最大能量积 Maximum Energy Product硅含量对电器用的低碳钢片的最大好处 The Advantage of Using Silicon low Carbon Steel晶粒取向(Grain-Oriented)及非晶粒取向(Non-Oriented) Grain Oriented & Non-Oriented电器用硅 [硅] 钢片的最终用途及规格 End Usage and Designations of Electrical Steel Strip电器用的硅 [硅] 钢片之分类 Classification of Silicon Steel Sheet for Electrical Use电器用钢片的绝缘涂层 Performance of Surface Insulation of Electrical Steel Sheets晶粒取向电器用硅钢片主要工业标准 International Standard – Grain-Oriented Electrical Steel Silicon Steel Sheet for Electrical Use晶粒取向电器用硅钢片 Grain-Oriented Electrical Steel晶粒取向，定取向芯钢片及高硼定取向芯钢片之磁力性能及夹层系数 (日工标准及美材标准) Magnetic Properties and Lamination Factor of SI-ORIENT-CORE& SI-ORIENT-CORE-HI B Electrical Steel Strip (JIS and AISI Standard)退火 Annealing电器用钢片用家需自行应力退火原因 Annealing of the Electrical Steel Sheet退火时注意事项 Annealing Precautionary碳污染 Prevent Carbon Contamination热力应先从工件边缘透入 Heat from the Laminated Stacks Edges提防过份氧化 No Excessive Oxidation应力退火温度 Stress –relieving Annealing Temperature绝缘表面 Surface Insulation非晶粒取向电力用钢片的电力、磁力、机械性能及夹层系数 Lamination Factors of Electrical, Magnetic & Mechanical Non-Grain Oriented Electrical电器及家电外壳用镀层冷辘 [低碳] 钢片 Coated (Low Carbon) Steel Sheets for Casing,Electricals & Home Appliances镀铝硅钢片 Aluminized Silicon Alloy Steel Sheet镀铝硅合金钢片的特色 Feature of Aluminized Silicon Alloy Steel Sheet用途 End Usages抗化学品能力 Chemical Resistance镀铝(硅)钢片–日工标准 (JIS G3314) Hot-aluminum-coated sheets and coils to JIS G 3314镀铝(硅)钢片–美材试标准 (ASTM A-463-77)35.7 JIS G3314镀热浸铝片的机械性能 Mechanical Properties of JIS G 3314 Hot-Dip Aluminum-coated Sheets andCoils公差 Size Tolerance镀铝(硅)钢片及其它种类钢片的抗腐蚀性能比较 Comparsion of various resistance of aluminized steel & other kinds of steel镀铝(硅)钢片生产流程 Aluminum Steel Sheet, Production Flow Chart焊接能力 Weldability镀铝钢片的焊接状态(比较冷辘钢片) Tips on welding of Aluminized sheet in comparasion with cold rolled steel strip钢板 Steel Plate钢板用途分类及各国钢板的工业标准包括日工标准及美材试标准 Type of steel Plate & Related JIS, ASTM and Other Major Industrial Standards钢板生产流程 Production Flow Chart钢板订货需知 Ordering of Steel Plate不锈钢 Stainless Steel不锈钢的定义 Definition of Stainless Steel不锈钢之分类，耐腐蚀性及耐热性Classification, Corrosion Resistant & Heat Resistance of Stainless Steel铁铬系不锈钢片Chrome Stainless Steel马氏体不锈钢Martensite Stainless Steel低碳马氏体不锈钢Low Carbon Martensite Stainless Steel含铁体不锈钢Ferrite Stainless Steel镍铬系不锈钢Nickel Chrome Stainless Steel释出硬化不锈钢Precipitation Hardening Stainless Steel铁锰铝不锈钢Fe / Mn / Al / Stainless Steel不锈钢的磁性Magnetic Property & Stainless Steel不锈钢箔、卷片、片及板之厚度分类Classification of Foil, Strip, Sheet & Plate by Thickness表面保护胶纸Surface protection film不锈钢片材常用代号Designation of SUS Steel Special Use Stainless 表面处理 Surface finish 薄卷片及薄片(0.3至 2.9mm 厚之片)机械性能Mechanical Properties of Thin Stainless Steel(Thickness from 0.3mm to 2.9mm) – strip/sheet 不锈钢片机械性能(301, 304, 631, CSP) Mechanical Properties of Spring use Stainless Steel不锈钢–种类，工业标准，化学成份，特点及主要用途Stainless Steel – Type, Industrial Standard, Chemical Composition, Characteristic & end usage of the most commonly used Stainless Steel不锈钢薄片用途例End Usage of Thinner Gauge不锈钢片、板用途例Examples of End Usages of Strip, Sheet & Plate不锈钢应力退火卷片常用规格名词图解General Specification of Tension Annealed Stainless Steel Strips耐热不锈钢Heat-Resistance Stainless Steel镍铬系耐热不锈钢特性、化学成份、及操作温度Heat-Resistance Stainless Steel铬系耐热钢Chrome Heat Resistance Steel镍铬耐热钢Ni - Cr Heat Resistance Steel超耐热钢Special Heat Resistance Steel抗热超级合金Heat Resistance Super Alloy耐热不锈钢比重表Specific Gravity of Heat – resistance steel plates and sheets stainless steel不锈钢材及耐热钢材标准对照表Stainless and Heat-Resisting Steels发条片 Power Spring Strip发条的分类及材料 Power Spring Strip Classification and Materials上链发条 Wind-up Spring倒后擦发条 Pull Back Power Spring圆面("卜竹")发条 Convex Spring Strip拉尺发条 Measure Tape魔术手环 Magic Tape魔术手环尺寸图 Drawing of Magic Tap定型发条 Constant Torque Spring定型发条及上炼发条的驱动力 Spring Force of Constant Torque Spring and Wing-up Spring定型发条的形状及翻动过程 Shape and Spring Back of Constant Torque Spring定型发条驱动力公式及代号The Formula and Symbol of Constant Torque Spring边缘处理 Edge Finish硬度 Hardness高碳钢化学成份及用途 High Carbon Tool Steel, Chemical Composition and Usage每公斤发条的长度简易公式 The Length of 1 Kg of Spring Steel Strip SK-5 & AISI-301每公斤长的重量 /公斤(阔 100-200公厘) Weight per one meter long (kg) (Width 100-200mm) SK-5 & AISI-301每公斤之长度 (阔 100-200公厘) Length per one kg (Width 100-200mm) SK-5 & AISI-301每公尺长的重量 /公斤(阔 2.0-10公厘) Weight per one meter long (kg) (Width 2.0-10mm) SK-5 & AISI-301每公斤之长度 (阔 2.0-10公厘) Length per one kg (Width 2.0-10mm)高碳钢片 High Carbon Steel Strip分类 Classification用组织结构分类 Classification According to Grain Structure用含碳量分类–即低碳钢、中碳钢及高碳钢 Classification According to Carbon Contains弹簧用碳钢片 Carbon Steel Strip For Spring Use冷轧状态 Cold Rolled Strip回火状态 Annealed Strip淬火及回火状态 Hardened & Tempered Strip/ Precision – Quenched Steel Strip贝氏体钢片 Bainite Steel Strip弹簧用碳钢片材之边缘处理 Edge Finished淬火剂 Quenching Media碳钢回火 Tempering回火有低温回火及高温回火 Low & High Temperature Tempering高温回火 High Temperature Tempering退火 Annealing完全退火 Full Annealing扩散退火 Diffusion Annealing低温退火 Low Temperature Annealing中途退火 Process Annealing球化退火 Spheroidizing Annealing光辉退火 Bright Annealing淬火 Quenching时间淬火 Time Quenching奥氏铁孻回火 Austempering马氏铁体淬火 Marquenching高碳钢片用途 End Usage of High Carbon Steel Strip冷轧高碳钢–日本工业标准 Cold-Rolled (Special Steel) Carbon Steel Strip to JIS G3311电镀金属钢片 Plate Metal Strip电镀金属捆片的优点Advantage of Using Plate Metal Strip金属捆片电镀层 Plated Layer of Plated Metal Strip镀镍 Nickel Plated镀铬 Chrome Plated镀黄铜 Brass Plated基层金属 Base Metal of Plated Metal Strip低碳钢或铁基层金属 Iron & Low Carbon as Base Metal不锈钢基层金属 Stainless Steel as Base Metal铜基层金属 Copper as Base Metal黄铜基层金属 Brass as Base Metal轴承合金 Bearing Alloy轴承合金–日工标准 JIS H 5401 Bearing Alloy to JIS H 5401锡基、铅基及锌基轴承合金比较表 Comparison of Tin base, Lead base and Zinc base alloy for Bearing purpose易溶合金 Fusible Alloy焊接合金 Soldering and Brazing Alloy软焊 Soldering Alloy软焊合金–日本标准 JIS H 4341 Soldering Alloy to JIS H 4341硬焊 Brazing Alloy其它焊接材料请参阅日工标准目录 Other Soldering Material细线材、枝材、棒材 Chapter Five Wire, Rod & Bar线材/枝材材质分类及制成品 Classification and End Products of Wire/Rod铁线(低碳钢线)日工标准 JIS G 3532 Low Carbon Steel Wires ( Iron Wire ) to JIS G 3532光线(低碳钢线)，火线 (退火低碳钢线 )，铅水线 (镀锌低碳钢线)及制造钉用低碳钢线之代号、公差及备注 Ordinary Low Carbon Steel Wire, Annealed Low Carbon Steel Wire, Galvanized low Carbon Steel Wire & Low Carbon Steel Wire for nail manufacturing - classification, Symbol of Grade, Tolerance and Remarks.机械性能 Mechanical Properites锌包层之重量，铜硫酸盐试验之酸洗次数及测试用卷筒直径 Weight of Zinc-Coating, Number of Dippings in Cupric Sulphate Test and Diameters of Mandrel Used for Coiling Test冷冲及冷锻用碳钢线枝 Carbon Steel Wire Rods for Cold Heading & Cold Forging (to JIS G3507) 级别，代号及化学成份 Classification, Symbol of Grade and Chemical Composition直径公差，偏圆度及脱碳层的平均深度 Diameter Tolerance, Ovality and Average Decarburized Layer Depth冷拉钢枝材 Cold Drawn Carbon Steel Shafting Bar枝材之美工标准，日工标准，用途及化学成份 AISI, JIS End Usage and Chemical Composition of Cold Drawn Carbon Steel Shafting Bar冷拉钢板重量表 Cold Drawn Steel Bar Weight Table高碳钢线枝 High Carbon Steel Wire Rod (to JIS G3506)冷拉高碳钢线 Hard Drawn High Carbon Steel Wire (to JIS G3521, ISO-84580-1&2)化学成份分析表 Chemical Analysis of Wire Rod线径、公差及机械性能(日本工业标准 G 3521) Mechanical Properties (JIS G 3521)琴线(日本标准 G3522) Piano Wires (to G3522)级别，代号，扭曲特性及可用之线材直径 Classes, symbols, twisting characteristic and applied WireDiameters直径，公差及拉力强度 Diameter, Tolerance and Tensile Strength裂纹之容许深度及脱碳层 Permissible depth of flaw and decarburized layer常用的弹簧不锈钢线-编号，特性，表面处理及化学成份 Stainless Spring Wire – National Standard number, Characteristic, Surface finish & Chemical composition弹簧不锈钢线，线径及拉力列表Stainless Spring Steel, Wire diameter and Tensile strength of Spring Wire处理及表面状况 Finish & Surface各种不锈钢线在不同处理拉力比较表 Tensile Strength of various kinds of Stainless Steel Wire under Different Finish圆径及偏圆度之公差 Tolerance of Wire Diameters & Ovality铬镍不锈钢及抗热钢弹簧线材–美国材验学会 ASTM A313 – 1987 Chromium – Nickel Stainless and Heat-resisting Steel Spring Wire – ASTM A313 – 1987化学成份 Chemical Composition机械性能 Mechanical Properties305, 316, 321及 347之拉力表 Tensile Strength Requirements for Types 305, 316, 321 and 347 A1S1-302贰级线材之拉力表 Tensile Strength of A1S1-302 Wire日本工业标准–不锈钢的化学成份 (先数字后字母排列) JIS –Chemical Composition of Stainless Steel (in order of number & alphabet)美国工业标准–不锈钢及防热钢材的化学成份 (先数字后字母排列) AISI – Chemical Composition of Stainless Steel & Heat-Resistant Steel(in order of number & alphabet)易车碳钢 Free Cutting Carbon Steels (to JIS G4804 )化学成份 Chemical composition圆钢枝，方钢枝及六角钢枝之形状及尺寸之公差 Tolerance on Shape and Dimensions for Round Steel Bar, Square Steel Bar, Hexagonal Steel Bar易车(快削)不锈钢 Free Cutting Stainless Steel易车(快削)不锈钢种类 Type of steel易车(快削)不锈钢拉力表 Tensile Strength of Free Cutting Wires枝/棒无芯磨公差表 (μ) (μ = 1/100 mm) Rod/Bar Centreless Grind Tolerance易车不锈钢及易车钢之不同尺寸及硬度比较 Hardness of Different Types & Size of Free Cutting Steel 扁线、半圆线及异形线 Flat Wire, Half Round Wire, Shaped Wire and Precision Shaped Fine Wire 加工方法 Manufacturing Method应用材料 Material Used特点 Characteristic用途End Usages不锈钢扁线及半圆线常用材料 Commonly used materials for Stainless Flat Wire & Half Round Wire 扁线公差 Flat Wire Tolerance方线公差 Square Wire Tolerance。

SBN陶瓷英文文献

Ferroelectric and piezoelectric properties of tungsten substituted SrBi 2Ta 2O 9ferroelectric ceramicsIndrani Coondoo *,S.K.Agarwal a ,A.K.Jha ba Superconductivity and Cryogenics Division,National Physical Laboratory,Dr K.S.Krishnan Road,New Delhi 110012,India bDepartment of Applied Physics,Delhi College of Engineering,Bawana Road,Delhi 110042,India1.IntroductionDefects in crystals signiﬁcantly inﬂuence physical and various other properties of materials [1].For instance,as it is well known,doping by other elements leads to signiﬁcant changes in the electrical properties of silicon.Historically,‘‘defect engineering’’has been developed in the ﬁeld of semiconducting materials such as compound semiconductors as well as in diamond,Si and Ge [2–4].Subsequently,the concept of defect engineering has been applied to other functional materials,and the signiﬁcant improve-ment in material properties have been achieved in high transition-temperature superconductors [5],amorphous SiO 2[6],photonic crystals [7]and also in the ﬁeld of ferroelectrics,such as BaTiO 3,Pb(Ti,Zr)O 3(PZT),etc.[8,9].Various structural and electrical properties of bismuth layer-structured ferroelectrics (BLSF)are also strongly affected on deviation from stoichiometric composi-tions and defects have been recognized as a crucially important factor [10–13].It has been found that in BLSF small changes in chemical composition result in signiﬁcantly altered dielectric and ferroelectric properties including dielectric constant and remanent polarization.In SrBi 2Ta 2O 9(SBT)and SrBi 2Nb 2O 9(SBN),orthor-hombic structural distortions with non-centrosymmetric spacegroup A 21am cause spontaneous ferroelectric polarization (P s )along a axis [14,15].SBT,a member of the BLSF family,has occupied an important position among the Pb-free ferroelectric memory materials [16–18].Tungsten (W 6+)has recently been investigated as a dopant for bismuth titanates and lanthanum doped bismuth titanates,in which the remanent polarization was observed to enhance when a small amount of Ti 4+was substituted by W 6+[19,20].With the objective to improve structural,dielectric and ferroelectric proper-ties,the hexavalent tungsten (W 6+)was chosen as a donor cation for partial replacement of the pentavalent tantalum (Ta 5+)SBT.In this report,the effect of tungsten substitution in SBT (SBTW),on the microstructural,ferroelectric and piezoelectric properties is reported.The results including the improvement in polarization properties have been discussed.2.ExperimentalSamples of compositions SrBi 2(W x Ta 1Àx )2O 9(SBWT),with x =0.0,0.025,0.050,0.075,0.10and 0.20were synthesized by solid-state reaction method taking SrCO 3,Bi 2O 3,Ta 2O 5and WO 3(all from Aldrich)in their stoichiometric proportions.The powder mixtures were thoroughly ground and passed through sieve of appropriate size and then calcined at 9008C in air for 2h.The calcined mixtures were ground and admixed with about 1–1.5wt%polyvinyl alcohol (Aldrich)as a binder and then pressed at $300MPa into disk shaped pellets.The pellets were sintered at 12008C for 2h in air.Materials Research Bulletin 44(2009)1288–1292A R T I C L E I N F O Article history:Received 3October 2008Received in revised form 5December 2008Accepted 6January 2009Available online 15January 2009Keywords:A.CeramicsC.X-ray diffractionD.FerroelectricityA B S T R A C TTungsten substituted samples of compositions SrBi 2(W x Ta 1Àx )2O 9(x =0.0,0.025,0.050,0.075,0.10and 0.20)were synthesized by solid-state reaction method and studied for their microstructural,electrical conductivity,ferroelectric and piezoelectric properties.The X-ray diffractograms conﬁrm the formation of single phase layered perovskite structure in the samples with x up to 0.05.The temperaturedependence of dc conductivity vis-a`-vis tungsten content shows a decrease in conductivity,which is attributed to the suppression of oxygen vacancies.The ferroelectric and piezoelectric studies of the W-substituted SBT ceramics show that the remanent polarization and d 33values increases with increasing concentration of tungsten up to x 0.05.Such compositions with low conductivity and high P r values should be excellent materials for highly stable ferroelectric memory devices.ß2009Elsevier Ltd.All rights reserved.*Corresponding author.Present address:Liquid Crystal Group,National Physical Laboratory,Dr K.S.Krishnan Road,New Delhi 110012,India.Tel.:+919810361727;fax:+911125170387.E-mail address:indrani_coondoo@ (I.Coondoo).Contents lists available at ScienceDirectMaterials Research Bulletinj o ur n a l h o m e p a g e :w w w.e l se v i e r.c om /l oc a t e /m a t r e sb u0025-5408/$–see front matter ß2009Elsevier Ltd.All rights reserved.doi:10.1016/j.materresbull.2009.01.001X-ray diffractograms of the sintered samples were recorded using a Bruker diffractometer in the range 108 2u 708with CuK a radiation.The sintered pellets were polished to a thickness of 1mm and coated with silver paste on both sides for use as electrodes and cured at 5508C for half an hour.Electrical conductivity was performed using Keithley’s 6517A Electrometer.The polarization–electric ﬁeld (P –E )hysteresis measurements were done at room temperature using an automatic P –E loop tracer based on Sawyer–Tower circuit.Piezoelectric charge co-efﬁcient d 33was measured using a Berlincourt d 33meter after poling the samples in silicone–oil bath at 2008C for half an hour under a dc electric ﬁeld of 60–70kV/cm.3.Results and discussion3.1.Structural and micro-structural studiesThe phase formation and crystal structure of the ceramics were examined by X-ray diffraction (XRD),which is shown in Fig.1.The XRD patterns of the samples show the characteristic peaks of SBT.The peaks have been indexed with the help of a computer program–POWDIN [21]and the reﬁned lattice parameters are given in Table 1.It is observed that a single phase layered perovskite structure is maintained in the range 0.0 x 0.05.Owing to the same co-ordination number i.e.6and the smallerionic radius of W (0.60A˚)in comparison to Ta (0.64A ˚),there is a high possibility of tungsten occupying the tantalum site.The observance of unidentiﬁed peak of very low intensity in the compositions with x >0.05indicates the solubility limit of W concentration in SBT.The unidentiﬁed peak is possibly due to tungsten not occupying the Ta sites in the structure as the intensity of this peak is observed to increase with tungsten content.Composition and sintering temperature inﬂuences the micro-structure such as grain growth and densiﬁcation of the specimen,which in turn control other properties of the material [11,13].The effects of W substitution on the microstructure have been examined by SEM and the obtained micrographs are shown in Fig.2.It shows the microstructure of the fractured surface of the studied samples.It is clearly observed that W substitution has pronounced effect on the average grain size and homogeneity of the grains.Randomly oriented and anisotropic plate-like grains are observed in all the samples.It is also observed that the average grain size increases gradually with increasing W content.The average grain size in the sample with x =0.0is $2–3m m while that in the sample with x =0.20the size increases to $5–7m m.3.2.Electrical studiesThe electrical conductivity of ceramic materials encompasses a wide range of values.In insulators,the defects w.r.t.the perfect crystalline structure act as charge carriers and the consideration of charge transport leads necessarily to the consideration of point defects and their migration [22].Many mechanisms were put forward to explain the conductivity mechanism in ceramics.Most of them are approximately divided into three groups:electronic conduction,oxygen vacancies ionic conduction,and ionic and p-type mixed conduction [22].Intrinsic conductivity results from the movement of the component ions,whereas conduction resulting from the impurity ions present in the lattice is known as extrinsic conductivity.At low temperature region (ferroelectric phase),the conduction is dominated by the extrinsic conduction,whereas the conduction at the high-temperature paraelectric phase ($300–7008C)is dominated by the intrinsic ionic conduction [23,25].Fig.3shows the temperature dependence of dc conductivity (s dc )for the undoped and doped SBT samples.The curves show that the conductivity increases with temperature.This is indicative of negative temperature coefﬁcient of resistance (NTCR)behavior,a characteristic of dielectrics [22].It is observed in Fig.3that throughout the temperature range,the dc conductivity of the doped samples are nearly two to three orders lower than that of the undoped sample.Two predominant conduction mechanisms indicated by slope changes in the two different temperature regions are observed in Fig.3.Such changes in the slope in the vicinity of the ferro-paraelectric transition region have been observed in other ferroelectric materials as well [23,24].In addition,it is also observed (Table 2)that the activation energy calculated using the Arrhenius equation [22]in the paraelectric phase increase from $0.80eV for the undoped sample to $2eV for the doped samples.The X-ray photoemission spectroscopic study has conﬁrmed that when Bi 2O 3evaporates during high-temperature processing,vacancy complexes are formed in the (Bi 2O 2)2+layers [26].As a result,defective (Bi 2O 2)2+layers are inherently present in SBT.The undoped SBT shows n-type conductivity,since when oxygen vacancies are created,it leaves behind two trapped electrons [27]:O o !12O 2"þV o þ2e 0(1)where O o is an oxygen ion on an oxygen site,V o is a oxygen vacant site and e 0represents electron.The conductivity in the perovskites can be described as an ordered diffusion of oxygen vacancies [28].Their motion is manifested by enhanced ionic conductivity associated with an activation energy value of $1eV [26].These oxygen vacancies can be suppressed by addition of donors,since the donor oxide contains more oxygen per cation than the host oxide it replaces [29].It has been reported that conductivity in Bi 4Ti 3O 12(BIT)can be signiﬁcantly decreased,up to three orders of magnitude with the addition of donors,such as Nb 5+and Ta 5+at the Ti 4+sites [23,30].A few other studies on layered perovskites have also reported a decrease inconductivityFig.1.XRD patterns of SrBi 2(W x Ta 1Àx )2O 9samples sintered at 12008C.Table 1Lattice parameters of SrBi 2(W x Ta 1Àx )2O 9samples.Concentration of W a (A ˚)b (A ˚)c (A ˚)0.0 5.5212 5.513924.92230.025 5.5214 5.520225.10790.05 5.5217 5.519925.05850.075 5.5191 5.504525.05670.10 5.5142 5.506125.0850.205.51335.493925.0861I.Coondoo et al./Materials Research Bulletin 44(2009)1288–12921289with addition of donors [23,24,31].In the present study,the Ta 5+-site substitution by W 6+in SBT can be formulated using a defect chemistry expression as WO 3þV o!Ta 2O 512W Ta þ3O o (2)It shows that the oxygen vacancies are reduced upon the substitution of donor W 6+ions for Ta 5+ions.Hence,it is reasonable to believe that the conductivity in SBT is suppressed by donor addition.As per the above discussion,the high s dc observed in the undoped SBT (Fig.3)can be attributed to the motion of oxygen vacancies.As already discussed,the doped samples show reduced conductivity because the transport phenomena involving oxygen vacancies are greatly reduced.The high E a value of $1.75–2eVcorresponding to the high-temperature region in the doped ceramics is consistent with the fact that in the donor-doped materials,the ionic conduction reduces [32].The activation energy E a in the low temperature ferroelectric region (Table 2)corre-sponds to extrinsic conduction.At lower temperatures the extrinsic conductivity results from the migration of impurity ions in the lattice.Some of these impurities may also be associated with lattice defects.Pure SBT has large number of Schottky defects (oxygen vacancies)in addition to impurity ions whereas in the doped samples,due to charge neutrality,there is relatively less content of oxygen vacancies.Thus,in the doped samples the conductivity in the low temperature region is largely due to the impurity ions only.This explains the high activation energy in pure SBT in the low temperature region compared to doped samples (Table 2).In the high-temperature region,the value of E a in the doped samples is observed to increase with W concentration up to x =0.05but beyond that,it decreases (Table 2).The decrease in the activation energy for samples with x >0.05suggests an increase in the concentration of mobile charge carriers [33].This observation can be ascribed to the existence of multiple valence states of tungsten.Since tungsten is a transitional metal element,the valence state of W ions in a solid solution most likely varies from W 6+to W 4+depending on the surrounding chemical environment [34].When W 4+are substituted for the Ta 5+sites,oxygen vacancies would be created,i.e.one oxygen vacancy would be created for every two tetravalent W ions entering the crystal structure,whichFig.3.Variation of dc conductivity with temperature in SrBi 2(W x Ta 1Àx )2O 9samples.Fig.2.SEM micrographs of fractured surfaces of SrBi 2(W x Ta 1Àx )2O 9samples with (a)x =0.0,(b)x =0.025,(c)x =0.050,(d)x =0.075,(e)x =0.10and (f)x =0.20Table 2Activation energy (E a )in the high-temperature paraelectric region and low temperature ferroelectric region;Curie temperature (T c )in SrBi 2(W x Ta 1Àx )2O 9samples.Concentration of W E a (high temp.)(eV)E a (low temp.)(eV)T c (8C)0.00.790.893110.025 1.920.593080.05 1.960.543250.075 1.940.543380.10 1.860.573680.201.740.54390I.Coondoo et al./Materials Research Bulletin 44(2009)1288–12921290explains the increase in the concentration of mobile charge carriers which ultimately results in an decrease in the E a beyond x>0.05. Hence it is reasonable to conclude that W ions in the SBWT exists as a varying valency state,i.e.at lower doping concentration they exist in hexavalent state(W6+)and at a higher doping concentra-tion,they tend to exist in lower valency states[8].The P–E loops of SrBi2(Ta1Àx W x)2O9are shown in Fig.4.It is observed that W-doping results in formation of well-deﬁned hysteresis loops.Fig.5shows the compositional dependence of remanent polarization(2P r)and the coerciveﬁeld(2E c)of SrBi2(Ta1Àx W x)2O9samples.Both the parameters depend on W content of the samples.It is observed that2P rﬁrst increases with x and then decreases while2E cﬁrst decreases with x and then increases(Fig.5).The optimum tungsten content for maximum2P r ($25m C/cm2)is observed to be x=0.075.It is known that ferroelectric properties are affected by compositional modiﬁcation,microstructural variation and lattice defects like oxygen vacancies[10,35,36].In hard ferroelectrics, with lower valent substituents,the associated oxide vacancies are likely to assemble in the vicinity of domain walls[37,38].These domains are locked by the defects and their polarization switching is difﬁcult,leading to an increase in E c and decrease in P r[38]. On the other hand,in soft ferroelectrics,with higher valent substituents,the defects are cation vacancies whose generation in the structure generally increases P r.Similar observations have been made in many reports[38–41].Watanabe et al.[42]reported a remarkable improvement in ferroelectric properties in the Bi4Ti3O12ceramic by adding higher valent cation,V5+at the Ti4+ site.It has also been reported that cation vacancies generated by donor doping make domain motion easier and enhance the ferroelectric properties[43].Further,it is known that domain walls are relatively free in large grains and are inhibited in their movement as the grain size decreases[44].In the larger grains, domain motion is easier which results in larger P r.Also for the SBT-based system,it is known that with increase in the grain size the remanent polarization also increases[45,46].Based on the obtained results and above discussion,it can be understood that in the undoped SBT,the oxygen vacancies assemble at sites near domain boundaries leading to a strong domain pinning.Hence,as observed,well-saturated P–E loop for pure SBT is not obtained.But in the doped samples,the suppression of the oxygen vacancies reduces the pinning effect on the domain walls,leading to enhanced remanent polarization and lower coerciveﬁeld.Also,the increase in grain size in tungsten added SBT,as observed in SEM micrographs(Fig.2)contribute to the increase in polarization values.In the present study,the grain size is observed to increase with increasing W concentration.However, the2P r values do not monotonously increase and neither the E c decreases continuously with increasing W concentration(Fig.5). The variation of P r and E c beyond x>0.05,seems possibly affected by the presence of secondary phases(observed in XRD diffracto-grams),which hampers the switching process of polarization [47–50].Also,beyond x>0.05the increase in the number of charge carriers in the form of oxygen vacancies leads to pinning of domain walls and thus a reduction in the values of P r and increase in E c is observed.Fig.6shows the variation of piezoelectric charge coefﬁcient d33 with x in the SrBi2(Ta1Àx W x)2O9.The d33values increases with increase in W content up to x=0.05.A decrease in d33values is observed in the samples with x!0.075.The piezoelectric coefﬁcient,d33,increases from13pC/N in the sample with x=0.0to23pC/N in the sample with x=0.05.It is known that the major drawback of SBT is its relatively higher conductivity,which hinders proper poling[51].High resistivity is therefore important for maintenance of poling efﬁciency at high-temperature[52,53].The W-doped SBT samples show an electrical conductivity value up to three orders of magnitude lower than that of undoped sample(Fig.3).The positional variation of2P r and2E c in SrBi2(W x Ta1Àx)2O9samples.Fig.6.Variation of d33in SrBi2(W x Ta1Àx)2O9samples.Fig. 4.P–E hysteresis loops in SrBi2(W x Ta1Àx)2O9samples recorded at roomtemperature.I.Coondoo et al./Materials Research Bulletin44(2009)1288–12921291decrease in conductivity upon donor doping improve the poling efﬁciency resulting in the observed higher d33values.Moreover, since the grain size increases with W content in SBT,it is reasonable to believe that the increase in grain size will also contribute to the increase in d33values[54].The decrease in the value of d33for samples with x!0.075is possibly due to the presence of secondary phases as observed in diffractograms[1,51,55]and the increase in oxygen vacancies for samples with x>0.05.4.ConclusionsX-ray diffractograms of the samples reveal that the single phase layered perovskite structure is maintained in the samples with tungsten content x0.05.SEM micrographs reveal that the average grain size increases with increase in W concentration. The temperature dependence of the electrical conductivity shows that tungsten doping results in the decrease of conductivity by up to three order of magnitude compared to W free SBT.All the tungsten-doped ceramics have higher2P r than that of the undoped sample.The maximum2P r($25m C/cm2)is obtained in the composition with x=0.075.The reduced conductivity allows high-temperature poling of the doped samples.Such compositions with low loss and high P r values should be excellent materials for highly stable ferroelectric memory devices.The d33value is observed to increase with increasing W content up to x0.05.The value of d33 in the composition with x=0.05is$23pC/N as compared to$13 pC/N in the undoped sample.AcknowledgmentsThe authors sincerely thank Prof.P.B.Sharma,Dean,Delhi College of Engineering,India for his generous support and providing ample research infrastructure to carry out the research work.The authors are thankful to Dr.S.K.Singhal,Scientist, National Physical 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成分和过冷度对亚共晶Fe-B合金的凝固速率和硬度的影响

第40卷第6期2020年12月西安工业大学学报Journal of Xi'an Technological UniversityVol40No6Dec2020DOI:10.16185/.2020.06.006成分和过冷度对亚共晶Fe-B合金的凝固速率和硬度的影响‘许军锋，杨恬，汪肖，坚增运(西安工业大学陕西省光电功能材料与器件重点实验室，西安710021)摘要：为了探究成分和过冷度对亚共晶Fe-B合金的凝固速率和硬度的影响，文中采用熔融玻璃净化法和高速摄影技术，对比研究了两种成分Fe-B亚共晶合金的共晶凝固行为差异。

实验结果表明，初生相和共晶相转变速率都会随形核过冷度增大而增大;但在同一形核过冷度下，硼含量增加，初生相转变速率减小，而共晶相转变速率增大。

采用硬度排序法分析凝固组织的硬度发现，随凝固过冷度的增加，-Fe相硬度值不断增加，而Fe2B相硬度值逐渐减小，并且样品整体硬度变化区间缩小。

由于硬度主要决定于硼元素含量，所以样品的硼元素随着过冷度增加分布趋于均匀化。

关键词：过冷度；显微硬度；再辉速率；界面迁移速率中图号：TG111.4文献标志码：A文章编号：1673-9965(2020)06-0631-07Effect of Composition and Undercooling on the Solidification Rate and Hardness of Hypoeutectic Fe-B AlloyXU Junfeng,YANG Tian^WANG Xiao,IAN Zengyun(TheShaanxiKeyLaboratoryofPhotoelectricFunctionalMaterialsandDevices,Xi'an Technological University,Xi?an710021,China)Abstract:In order to examine the effect of composition and undercooling on the solidification rate and hardness of hypoeutectic Fe-B alloy,contrastive study is conducted of the solidification behavior of two hypoeutectic Fe-B alloys by the fluxing glass purification method and high-speed photography technology．Theresultsshowthatthehigherthenucleationundercooling,thegreaterthetransformation rates of the primary phase and the eutectic phase.However,at the same undercooling,the greater the boroncontent,thelowertheprimarytransformationrateandthehighertheeutectictransitionrate An analysis of the microstructure hardness by the sorted method shows that,with the increase of solidification undercooling,the hardness value of the crFe phase increases,while the hardness of the Fe B*收稿日期：2020-10-13基金资助：陕西省科技新星项目(016KJXX87)陕西省教育厅重点实验室项目(18JS050)。

the chinese medicine(TCM)—中药四气五味英语介绍

sweet
1.functions of tonifying 补益 2.harmonizing of middle warmer 和中 3.regulating （调节）herbal property 调和药性 4.alleviating pain 缓急止痛
sour
1.has the action of astringing （[ə‘strɪndʒ] vt. 使……收缩；使……收敛）收敛 2.inducing astringenБайду номын сангаасy （[ə‘strɪndʒənsi] n. 收敛性；严酷，严峻）固涩
It
The five flavors
五味
The Five Flavors（五味）
It
contains five basic herbal(adj 药草的，草本的) medicines in a prescription（药味）—pungent [‘pʌndʒənt]（adj 辛的 )，sweet, sour, bitter, and salty . can divided into two parts
It
Yin : pungent， sweet Yang： sour, bitter, and salty
pungent
1.funtion of volatilization [,vɑlətɪlɪ'zeʃən] （挥发性）发散 2.promoting the circulation of Qi 行气 3.Invigorating [ɪn'vɪgəreɪtɪŋ] （使生气勃勃）the circulation of blood 活血 4.treat exterior [ɪk‘stɪrɪɚ] （ n.外部表面） syndrome 解表 such as herbal ephedra ['ɛfədrɚ] 麻黄

激光熔融技术

Journal of Materials Processing Technology 211(2011)750–758Contents lists available at ScienceDirectJournal of Materials ProcessingTechnologyj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /j m a t p r o t ecPerformance of a cutting tool made of steel matrix surface nano-composite produced by in situ laser melt injection technologyO.Verezub a ,Z.Kálazi b ,A.Sytcheva c ,L.Kuzsella d ,G.Buza b ,N.V.Verezub e ,A.Fedorov f ,G.Kaptay g ,h ,∗aUni.Miskolc,Dep.Production Eng.,Egyetemvaros,3515Miskolc,HungarybBAY-ATI (RI for Materials Science and Engineering),Fehervari ut 130,Budapest,Hungary cBAY-NANO (RI for Nanotechnology),Dep.Nano-metrology,3515Miskolc,Egyetemvaros,E/7,Hungary dUni.Miskolc,Dep.Polimer Eng.,Egyetemvaros,3515Miskolc,Hungary eNational Technical University (“Kharkov Polytechnical Institute”),Frunze st.21,Dep.Integrated Technologies in Machine Building,Kharkov,Ukraine fARC -The Australian Reinforcing Company,518Ballarat Road,Sunshine,3020VIC,Melbourne,Australia gBAY-NANO (RI for Nanotechnology),Dep.Nano-composites and Uni.Miskolc,Egyetemvaros,E/7,3515Miskolc,Hungary hUniversity of Miskolc,Dep.Nanotechnology,Egyetemvaros,E/7,3515Miskolc,Hungarya r t i c l e i n f o Article history:Received 15May 2010Received in revised form 4December 2010Accepted 7December 2010Available online 15December 2010Keywords:Cutting toolMetal matrix nano-composite Laser processing Tool-lifea b s t r a c tSteel-matrix (105WCr6steel)surface nano-composites with (Ti,W)C micron-sized and (Fe,W)6C nano-sized carbide precipitates were produced by in situ laser melt injection technology with subsequent heat treatment.The microhardness of a 1mm thick nano-composite layer was found to be higher than that of the initial matrix.The machinability of the surface nano-composite by a cubic boron nitride (CBN)wheel was found lower,but still reasonable compared to the initial matrix.Cutting tools produced from our new nano-composite by the CBN wheel were found to have higher wear resistance,longer tool life and provided lower cutting forces against a C45steel workpiece compared to the initial matrix of the nano-composite.©2010Elsevier B.V.All rights reserved.1.IntroductionMaterial removal and machining processes play a key role in generating value-added activities to materials and machine parts since their introduction about 3centuries ago (Shaw,2005).Nev-ertheless,there is a constant interest in this ﬁeld due to the high variety of newly developed materials (Biswas,2006)and superhard coatings (Veprek and Veprek-Heijman,2008)that can be used as cutting tools.The optimum combination of hard particles and duc-tile metallic matrices can lead to higher wear resistance.As this principle is widely recognized,particles reinforced metal matrix composites (MMCs)have been developed for cutting tools in a Al-matrix composites (Uday et al.,2009)and in steel matrix com-posites (Li et al.,2010).Among many requirements to cutting tools,cost is always at the top of the list.That is why this research was concentrated on the∗Corresponding author at:BAY-NANO (RI for Nanotechnology),Dep.Nano-composites and Uni.Miskolc,Egyetemvaros,E/7,3515Miskolc,Hungary.Tel.:+36304150002;fax:+3646362916.E-mail addresses:olga ver79@mail.ru (O.Verezub),kalazi@bzaka.hu (Z.Kálazi),kubaisy@mail.ru (A.Sytcheva),femkuzsy@uni-miskolc.hu(L.Kuzsella),buza@bzaka.hu (G.Buza),nikverezub@mail.ru (N.V.Verezub),FedorovA@.au (A.Fedorov),kaptay@ (G.Kaptay).cheapest possible steel matrix.To keep the cost of the cutting tool low,only the surface layer of the cutting tool will be improved,i.e.steel -matrix surface composites will be considered in this paper.It has been established by Iglesias et al.(2007)that the wear resistance of the composite increases with decreasing the size of the hard,reinforcing particles.That is why a special technology has been developed by Verezub et al.(2009)to ensure that the reinforc-ing particles are as small as ing smaller hard particles in the steel matrix of the cutting tool is expected to improve the performance of the cutting tool.There is a wide variety of reinforcing particles for the steel matrix.The most ‘popular’particles are TiC particles (Ala-Kleme et al.,2007)and WC particles embedded in the matrix of M2high-speed tool steels (Riabkina-Fishman et al.,2001)or in Ni–Cr matrix (St-Georges,2007).These particles are hard and thermodynami-cally stable.While TiC has superiority in both hardness (Kalpakjian,1995)and thermodynamic stability (Barin,1993)over WC,both of these particles are metallic in nature,and thus are well wettable by the steel matrix ensuring strong adhesion between the matrix and the reinforcing particles.This is essential to prevent reinforc-ing particles to turn out of the matrix without being worn,what is known to be one of the wear mechanisms of MMCs (Kaptay et al.,1997).In this respect WC is superior to TiC,as WC is perfectly wet-ted,while TiC is only moderately wetted by liquid steel as reviewed0924-0136/$–see front matter ©2010Elsevier B.V.All rights reserved.doi:10.1016/j.jmatprotec.2010.12.009O.Verezub et al./Journal of Materials Processing Technology211(2011)750–758751Table1Composition(in wt%)of the HVG steel(similar to105WCr6steel)(balance:Fe).C Mn Si S P Cu Cr Ni Al Ti Mo Nb W V O0.99 1.000.380.0140.0210.14 1.030.190.0280.0050.10.01 1.340.030.0056by Eustathopoulos et al.(1999)and shown theoretically by Kaptay (2005).Among the many possible technologies to produce steel matrix surface nano-composites,the laser melt injection(LMI)technology has been selected by the authors.This technology was developed 3decades ago by Ayers and Tucker(1980)to produce a surface composite layer.In this technique large(around100␮m)carbide particles are blown by a gas stream into a moving laser melted pool of a substrate metal.The method is superior to all coating technologies in providing perfect adhesion between the compos-ite and the substrate and also in providing large thickness(around 1mm)allowing to re-ground the cutting ter the LMI tech-nology has been proven to be efﬁcient to produce WC particles reinforced steel matrix composites by Liu et al.(2008),using par-ticularly X40CrMoV5–1steel surface layer by Dobrzanski et al. (2005)and duplex stainless steels matrix by Do Nascimento et al. (2008).The combination of WC+Co particles was used by Bitay and Roósz(2006).TiC particles were added into liquid steel by Fábián et al.(2003).The drawback of LMI technology is that only large carbide par-ticles with a sufﬁciently large kinetic energy can break the high surface tension liquid metal/gas interface,as was proven for liq-uid steel by Farias and Irons(1985)and for liquid aluminum by Vreeling et al.(2000).This is especially true for low-density TiC particles(compared to the density of liquid steel)that are not‘per-fectly’wetted by liquid steel as shown by Verezub et al.(2005). In fact,incorporation problems for the TiC/liquid steel couple was mentioned in the veryﬁrst paper by Ayers and Tucker(1980)and was later conﬁrmed by Králik et al.(2003).Thus,the steel rein-forcing matrix,the TiC particles,the LMI technique and the desire to produce surface nano-composite seem to be contradictory.To solve this problem,an in situ LMI technology was developed by Verezub et al.(2009)to produce steel matrix carbide reinforced surface nano-composites.The in situ production route of steel-matrix TiC reinforced composites has been known since the work by Terry and Chinyamakobvu(1991).This method has been developed further by using reaction casting by Feng et al.(2005)and high-energy electron beam irradiation by Lee et al.(2006).The method was extended to produce Fe/(TiW)C composite powder by Correa et al. (2007).Good tribological behaviour of TiC–ferrous matrix com-posites was shown by Kattamis and Suganuma(1990).The Fe/TiC composites were found to have excellent wear properties by Galgali et al.(1999),conﬁrmed also for elevated temperatures by Degnan et al.(2001).The sameﬁnding was extended by Dogan et al.(2001) for cast chromium steels reinforced by TiC particles.Nevertheless, the in situ production of Fe/TiC composites and the LMI technology was combined for theﬁrst time by Verezub et al.(2009).The goal of the present paper is to evaluate the machinability(upon producing a cutting tool from it)and also the performance as a cutting tool of a steel matrix(TiW)C reinforced surface nano-composite produced on a cheap steel matrix by the in situ LMI process.2.Materials and methods2.1.MaterialsLow-alloyed tool steel plates of grade HVG(Russian GOST5950-73,1973being the analogue of steel105WCr6)have been selected as a base material for the current research.Detailed chemical com-position of the HVG substrate is given in Table1.The initial size of the substrates was8mm×8mm×4mm.Additionally,tungsten carbide and metallic titanium powders of chemical purity,both with a particle size of45–70␮m were used.These two powders were mixed at a1:1molar ratio.This molar ratio was chosen as the most stable carbides in the Ti–W–C system are the TiC and WC car-bides,and in this way the exchange reaction Ti+WC=W+TiC can be ensured between them.Of-course,the C-content of the original steel will also play some role(see below).2.2.Production of the nano-compositesSchematic diagram of LMI-equipment used in the current study is shown in Fig.1.The upper8mm×8mm plane of the HVG sub-strate was coated by a thin layer of graphite to increase laser beam absorption efﬁciency during the LMI process.The other side of the steel substrate was brazed onto a large,water-cooled Cu-plate to ensure fast cooling of the substrate.The top surface of the substrate was melted by a2.5kW CO2continuous wave laser(type Trumph TLC105),with a laser spot of2mm in diameter.The laser spot was moving along the sample with a scanning speed of400mm/min. The(WC+Ti)powder mixture was blown into the melted pool at an angle of45◦using argon as carrier gas.The following three pow-der feeding rates were used during our experiments:1.3g/min, 2.3g/min and3.8g/min.Several laser tracks were drawn parallel to each other with a50%overlapping.After the LMI process,the rapidly cooled samples were heat treated under the following conditions:austenitizing at a tempera-ture of1000–1050◦C during10–15s in a high frequency induction furnace,followed by rapid cooling and tempering at a temperature of350◦C for1h.The second round of tempering was performed during1h at560◦C.For reasons of more correct comparison,the initial HVG samples were heat treated under usual conditions (hardening at840◦C and tempering at170◦C).The samples were grinded,polished,etched and analyzed uti-lizing special techniques.The microstructure of the substrates was observed using an AMRAY1810i SEM(Scanning Electron Microscopy with micro resolution),equipped with EDS(Energy Dispersive X-ray Spectroscopy).The identiﬁcation of nano-sized particles was performed by a high resolution SEM(HitachiS-4800,Fig.1.The schematic diagram of the laser melt injection(LMI)equipment(1–laser, 2–powder nozzle,3–steel substrate to be treated,4–copper cooling plate,5–working table,6–cooling water input and output).752O.Verezub et al./Journal of Materials Processing Technology211(2011)750–758Japan).Quantitative analysis of the samples was performed by ImageJ software.In different parts of the paper the following short sample names are used:i.“LMI”is the sample produced here by the LMI procedure includ-ing heat treatment.ii.“HVG”is the original HVG sample(see Table1)heat treated as described above.iii.“HSS”is a commercially available high speed steel sample with 6%W+5%Mo.2.3.Microhardness measurement of the nano-compositeThe microhardness proﬁles were measured using TUKON2100B equipment(Wilson Instr.)using load of500g and time of pressing of10s.The samples were polished and etched before the micro-hardness measurements.Microhardness was scanned along two lines:(i)perpendicular to the surface,as function of depth,and(ii) parallel along the surface,at the depth of0.40mm.2.4.Machinability of the nano-composite by cubic BN wheelA cubic boron nitride(CBN)grindingﬂaring cup wheel of type L010(125/100)–100%–B1–58(Russian standard)which cor-responds to grinding wheel B120C100vitriﬁed bond(Stephenson and Agapiou,2006)was used to remove small quantities of the sur-face composite material to produce the required shape and surface quality for the cutting tool insert.Additionally,the grinding ratio of the CBN wheel was studied by removing the same thickness of 1mm from each substrate(HVG,LMI,HSS).The grinding ratio G,is deﬁned as the ratio of worn mass of the grinding wheel(mg)to the mass of the removed material(g).The CBN wheel was studied by SEM+EDS after the grinding experiments.2.5.Performance of a cutting tool made of LMI nano-composite materialSteel C45(0.45%C+0.6%Mn+0.25%Si)was used as a workpiece for the cutting experiments.Machining of the steel C45workpiece was performed by the HVG,LMI and HSS cutting tools.All the exper-iments were run with the following cutting conditions:cutting speed V=20–60m/min,feed f=0.05–0.3mm/rev and depth of cut d=0.25–1.75mm.The cutting force components were measured by a piezoelectric dynamometer(Kistler).SEM and EDS analysis of the cutting tool and the removed chips were applied after the cutting experiments.3.Results and discussion3.1.Structure and composition of the nano-compositeFig.2shows SEM pictures of cross section of the characteristic LMI sample.Fig.2a shows that the depth of the surface composite layer is approximately1mm.Due to multiple scanning by the laser beam,the depth of the melted layer shows a certain pattern in Fig.2a,with minima in the depth separated by a distance of about 1mm(what is half of the2mm laser spot diameter due to50% of overlapping).As one can see from Fig.2,the microstructure of the melted layer seems to be macroscopically homogeneous.This is due to the high velocity of Marangoni convection of the laser melted pool during the LMI process.Fig.3shows enlarged SEM pictures of the LMI sample with two types of precipitates.The several micron sized(Ti,W)C carbide pre-cipitates(Fig.3a)formed during fast cooling at the latest stage ofthe Fig.2.SEM pictures of the cross sections of the steel substrate after the LMI treat-ment(a)and the general view of the microstructure within the laser treated zone (b)(powder feeding rate is2.3g/min).LMI process by in situ precipitation from the molten steel matrix. The core of these precipitates is rich in Ti,while the outer region of the precipitates is rich in W.This is so due to higher thermodynamic stability of TiC compared to WC.The second type of precipitates is below100nm in diameter and is formed only during the subse-quent heat treatment.These nano-particles are(Fe,W)6C carbides (Fig.3a and b),precipitating from the supersaturated solid steel matrix(for more details see Verezub et al.,2009).The volume%of micron sized(Ti,W)C particles are shown in Fig.4as function of the powder feeding rate.The theoretical maximum,shown in Fig.4was calculated from the technologi-cal parameters and from the cross section of the melted zone(see Fig.2a).One can see that in the as-received LMI samples the amount of incorporated(Ti,W)C particles is somewhat lower compared to the theoretical maximum.The incorporation ratio decreases from 89%(for1.3g/min)to76%(for3.8g/m)with increasing the pow-der feeding rate.It is probably due to the gradual increase in the effective viscosity of the suspension with increasing its solid con-tent,what makes further incorporation and dissolution of(Ti+WC) particles more difﬁcult.During heat treatment of the LMI samples, the volume%of micron-sized(Ti,W)C particles is decreased further by about20%.This is due to the partial dissolution of the W-rich outer region of the micron-sized(Ti,W)C precipitates.The amount of nano-sized(Fe,W)6C particles is found around25±5vol%,being independent of the powder feeding rate.These nano-sized particles form during the heat treatment,from the over-saturated matrix and partially from the dissolved outer regions of the micron-sized precipitates.As follows from materials balance,the majority of the content of these(Fe,W)6C nano-particles originate from the mate-rial of the matrix.Further investigation is needed to clarify howO.Verezub et al./Journal of Materials Processing Technology 211(2011)750–758753Fig.3.SEM micrographs of the cross section of the LMI sample in two different magniﬁcations (powder feeding rate is 2.3g/min).the conditions of heat treatment inﬂuence the micro-and nano-structure of the composite and the amount and size distribution of (Fe,W)6C particles.It should be mentioned that at the highest powder feeding rate of 3.8g/min the LMI samples appeared to be cracked.This is probably due to the too high volume %of the carbide phase in the matrix.The two other samples (produced at the powder feeding rates of 1.3and 2.3g/min)are free of cracks.The latter is more promising as the higher amount of carbide phase leads to improved mechanical properties of the composite,if the formation of cracks is avoided.3.2.Microhardness of the LMI nano-composite sampleThe depth proﬁle of microhardness of the LMI nano-composite sample with powder feeding rate of 2.3g/min is shown in Fig.5.All measurements are made after the heat treatment described in the experimental part.The depth proﬁle can be divided into three regions:010*******12345powder feeding rate, g/min(T i ,W )C , v o l %Fig.4.The volume %of the micron-sized (Ti,W)C particles as function of powder feeding rate after the LMI process (before and after the heat treatment procedure).020040060080010001200140000.51 1.52M i c r o h a r d n e s s , HVDistance from surface, mmFig.5.Depth proﬁle of microhardness of the LMI nano-composites (powder feeding rate is 2.3g/min).i.The upper surface layer of about 500␮m thickness has a highest microhardness of about 1200HV.ii.The initial substrate (below 1mm from the top surface)has a lowest microhardness of about 1000HV.iii.There is a transition zone between 500and 1000␮m measuredfrom the top surface,within which the microhardness gradually changes between the above mentioned limits.In evaluation of these results let us remind that carbon can diffuse from the non-melted part of the substrate into the melted LMI part of the substrate during the heat treatment.The increased microhardness of the upper surface layer of LMI nano-composite sample is obviously due to the precipitated micron-sized (Ti,W)C and nano-sized (Fe,W)6C hard carbide par-ticles.The existence of the intermediate zone could be due to the interplay between solidiﬁcation rate (solidiﬁcation goes from the bottom of the melted zone upwards)and the feeding and mixing rates of the added powder mixture (powder mixture is added to the top and the incorporated particles together with the dissolved atoms move downwards mainly by the Marangoni convection).In Fig.6a the measured microhardness is shown parallel along the sample surface,at the depth of about 0.4mm for both the as received LMI sample and the heat treated LMI sample.One can see that the microhardness of the LMI samples increase due to the heat treatment,what is probably due to the formation of (Fe,W)6C02004006008001000120014000.511.522.53M i c r o h a r d n e s s , H VDistance, mm00.20.40.60.8100.511.52 2.53d e p t h , m mdistance, mmFig.6.Microhardness scanned parallel along the surface,at the depth of about 0.4mm for both as received LMI sample and the heat treated LMI sample (a)and the depth of the melted pool as function of the same path (b)(see the pattern in Fig.2a).754O.Verezub et al./Journal of Materials Processing Technology 211(2011)750–7580.0340f , m m /p a s sv f ,/m i nFig.7.The grinding ratio of the LMI nano-composite sample (powder feeding rate is 2.3g/min,V =25m/s).nanoparticles.It is also obvious that the heat treatment ﬂatters out the large ﬂuctuations in the microhardness of the as received LMI sample.The minima in the microhardness ﬂuctuations (Fig.6a)approximately coincide with the minima in the depth of the melted zone (see Fig.6b and the pattern in Fig.2a).This can be explained by Fig.5,measured at the largest depth of the melted zone.The smaller is the depth of the melted zone,the higher becomes the relative depth of the same absolute depth of 0.4mm,and thus,in accordance with Fig.5,the smaller is the microhardness.As follows from Figs.5–6,the microhardness of the produced nano-composite layer is around 12GPa.For this value the optimum grinding wheel and the optimum workpiece to be machined should be selected such that the ratio of microhardnesses of the machining and that of the to be machined materials should be at least 3.As a machining tool,CBN (cubic boron-nitride)has been selected with its microhardness of about 50GPa (Kalpakjian,1995)being about 4.2times stronger compared to the hardness of our LMI sample.On the other hand,the C45workpiece has been selected with its microhardness of about 2.7GPa,being about 4.4times less strong compared to our LMI sample.Thus,the microhardness of our LMI nano-composite sample is positioned almost in the middle (in a logarithmic scale)of the interval between the microhardness val-ues of the machining CBN tool and that of the to be machined C45workpiece.3.3.Machinability of the LMI nano-composite by cubic BN wheel During the LMI treatment the surface of the substrate melts,and thus it becomes quite uneven after solidiﬁcation (the subsequent heat treatment does not provide any signiﬁcant improvement).As a result,the as-received LMI nano-composite sample cannot be used as a cutting tool.Therefore,the as-received LMI nano-composite sample was grinded by a CBN wheel to obtain the shape and surface quality required for cutting tools.Fig.7shows the grinding ratio of the LMI nano-composite sam-ple as function of the feed rate of the workpiece (v f ,m/min)and a feed (f ,mm/pass).The combination of a feed of f =0.04m/pass and a feed rate of v f =3m/min leads to a maximum grinding ratio of about G =45–50mg/g.Based on the results shown in Fig.7,the optimal grinding conditions are selected as:f =0.01–0.02mm/pass,v f =1–2m/min and V =25m/s.Under these conditions the grinding ratio can be kept at a reasonable level of G =8–15mg/g.In compari-son,under the same conditions the grinding ratio for the HVG steel was found to be 6.8mg/g,while the grinding ratio for HSS is known to be about 5–6mg/g (Lisanov,1978).The increased grinding ratio of our LMI sample is obviously due to the hard (Ti,W)C and (Fe,W)6C particles in the surface of newly developed material.Fig.8.The EDS spectra of CBN wheels after grinding HVG (a)and LMI (b)samples (powder feeding rate is 2.3g/min).In Fig.8the energy dispersive X-ray spectra of two CBN wheels are compared after identical grinding runs of the HVG and LMI samples.In addition to the C-and Fe-peaks after grinding the HVG sample,large W and Ti peaks are observed after grinding the LMI nano-composite sample.This can be explained by stabilisation of the C-content of the initial steel substrate by added Ti and by the attraction between (Ti,W)and (B,N)atoms,respectively,being due to the existence of stable titanium boride,titanium nitride and tungsten boride compounds as reported by Barin (1993).Thus,dur-ing the grinding process part of the Ti-and W-content of the LMI nano-composite substrate adheres to the CBN surface.The pres-ence of solid titanium and tungsten carbides causes loosening of the CBN grains and their fallout,leading to intensive wear of the wheel,also shown by Klimenko et al.(1996).Forming the rake and ﬂank surfaces during grinding of the LMI nano-composite samples resembles the grinding of high-speed steel cutting tools as shown by Mamalis et al.(2002).When the high quality alloyed layer is achieved,cutting edge without visible chip-ping is obtained.At the same time the edge roughness,as well as the radius of the cutting edge are higher for the HVG substrate com-pared to the LMI nano-composite substrate (Table 2).Increase of the feed rate and that of the feed lead to further increase in roughness of the tool’s cutting edge.Table 2Roughness of tool’s cutting edge and surfaces after grinding by CBN wheels (param-eters:V =25m/s,v f =2m/min,f =0.01mm/pass).Tool material Cutting edgeroughness R a ,␮m Roughness of rake and ﬂank surfaces R a ,␮m HSS 1.2–1.30.15–0.18LMI 1.3–1.50.17–0.20HVG1.4–1.60.21–0.24O.Verezub et al./Journal of Materials Processing Technology 211(2011)750–75875500,10,20,30,40,5050100150200machining time, minV B , m mFig.9.The inﬂuence of machining time on ﬂank wear for different cutting tool materials (V =25m/min,f =0.1mm/rev,d =0.5mm).Curves correspond to the HVG steel,LMI nano-composite produced with different powder feeding rates (ﬁgures on curves correspond to the unit of g/min),and HSS.Overall it can be concluded that CBN wheels can be used with optimum grinding parameters of f =0.01–0.02mm/pass,v f =1–2m/min and V =25m/s to convert the as-received LMI nano-composite into the cutting tool.The required shape and roughness of the cutting tool can be obtained with a reasonable grinding ratio of about G =8–15mg/g.3.4.Tool life of the cutting tool made of our nano-composite During testing of a new LMI nano-composite cutting tool on C45workpiece,crater wear was found to be negligible compared to ﬂank wear.These two types of wear are the most common measured forms of tool wear.Thus,the tool life of this newLMI2040608010012014016018001234powder feeding rate, g/mint o o l l i f e , m i nFig.10.Tool life as function of the powder feeding rate during the LMI process (V =25m/min,f =0.1mm/rev,d =0.5mm)(the point at zero feeding rate refers to a different heat history of a sample,that is why this point is connected to other points by a thin line).nano-composite cutting tool is determined from the measured ﬂank wear.Fig.9shows ﬂank wear measurements for HVG steel used as a base material,LMI nano-composite produced with different pow-der feeding rates and HSS.The critical ﬂank wear of 0.45mm was chosen based on values recommended for replacing or re-grounding alloyed tool materials (Kalpakjian,1995).The machining time during which the actual ﬂank wear achieves the critical value is called tool life (T ,min).Tool life as function of the powder feeding rate is shown in Fig.10.It shows that an optimum value of the powder feeding rate exists for the maximum tool life.When Fig.10is rationalized in combination with Fig.4,it can be seenthat the volume %of carbide particles in the compositeFig.11.SEM images of the cutting tool made of the LMI sample after its service (a–c)and EDS spectrum (d)of the worn surface.756O.Verezub et al./Journal of Materials Processing Technology211(2011)750–758Fig.12.Removed chip from steel C45by the LMI cutting tool(a)and its EDS spec-trum(b).gradually increases with the increase of powder feeding rate and,as a consequence,tool life also increases.However,as was mentioned above,cracks were formed in the substrate,made by the powder feeding rate of3.8g/min.As a result,a cutting tool made of this substrate has a lower tool life.One can suppose that there is an optimum feeding rate in the interval between2.3and3.8g/min, when the volume%of carbide particles is somewhat larger than for the2.3g/min feeding rate,but still without crack formation.The SEM images of the LMI nano-composite cutting tool faces after machining of C45steel are shown in Fig.11.Fig.11a shows the overlapping of the LMI tracks and the traces of theﬂank wear(mea-sured as0.45mm).In Fig.11b–c carbide particles being similar to those shown in Figs.2–3are shown.The difference is that the steel matrix is worn away in between the hard carbide particles after machining compared to the initial state of the LMI nano-composite substrate(compare Fig.11b–c to Figs.2–3).Therefore,it is evident that theﬂank wear is the result of abrasive wear of the LMI cutting tool.The EDS spectrum(Fig.11d)of the worn surface shows Fe,Ti, W as basic components.In Fig.12the SEM picture and EDS spectrum of the removed chip from the C45workpiece is shown,after its machining by the LMI nano-composite cutting tool.It can be seen that the removed chip is continuous,and the main elements of the nano-composite (Ti and W)are missing from its X-ray spectrum.Thus,there was no adhesion of Ti and/or W to the C45steel workpiece during its machining by the LMI nano-composite cutting tool.In order to position our cutting tool made of the LMI substrate on a tool-life scale,tool-life tests have been conducted.The effect of cutting speed V on tool-life T has been assessed using Taylor’s tool life equation(Eq.(1))(Taylor,1907)and the results are shown Table3Experimental tool life(T,min)of different cutting tool materials against C45work-piece(f=0.1mm/rev and d=0.5mm).V,m/min T,min(experimental)HVG LMI HSS20385500535 2550160190 30157088 3542550 40–1726 45–715 50–47 60–24in Table3.C1=V·T n(1) Eq.(1)is widely used and recognized in the industry.It relates tool life to the cutting speed through empirical tool life constants n and C1.Table4shows the range of values n and C1for different cutting tool materials obtained from the data in Table3.The data(Table4)indicate that the LMI process of inserting (TiW)C particles into HVG substrate improved tool life of the base material by300–400%when cutting speed V was25–35m/min. However,this new material was felt short to surpass tool life of HSS cutting material by just20%in the same cutting speed range.No sig-niﬁcant difference between tool life of HSS and LMI was observed during machining at20m/min.Performance of cutting tools made of LMI nano-composite is similar to the performance of HSS and is limited by wear resistance at cutting speeds above40–45m/min (Stephenson and Agapiou,2006).Cutting tools made of HVG steel can be used at speeds up to30m/min.3.5.Cutting force componentsDuring machining of the C45workpieces by the cutting tool made of HVG and LMI substrates,the two main force components F z (N)and F x(N)have been measured as function of the depth of cut d (mm)and feed f(mm/rev).The effects of depth of cut and feed on the measured F z and F x force components for the two different cutting materials(HVG and LMI nano-composite)are shown in Figs.13–14. The cutting speed increase within limits of V c=20–60m/min does not sufﬁciently inﬂuence the value of the cutting force(Fedorov, 2005)and therefore has not been tested in this paper.The effect of depth of cut d on the measured force components for two different cutting tool materials is shown in Fig.13a and b. Forces F z and F x increase with the increase in depth of cut because the increase in depth of cut leads to increase in the area of cut and length of the cutting edge in contact.The inﬂuence of feed f on the forces F z and F x is shown in Fig.14a and b.The increases in feed lead to increase in cut thickness,which,in turn,increases the area of cut and as a consequence,the force components.Figs.13–14show that machining with LMI nano-composite cut-ting tool material decreases cutting forces F z and F x in comparison with HVG cutting tool material.However,signiﬁcant force reduc-tions can only be observed when depth of cut is greater than1mm and feed is greater than0.2mm/rev.The force components can be described as function of parameters d and f by the followingTable4Values of n and C1for different tool materials(f=0.1mm/rev,d=0.5mm).Cutting tool material n C1HSS0.2280.89 LMI0.1967.18 HVG0.1241.58。

化学专业英语电子版

Chapter 1 Matter and MeasurementChemistry is the science of matter and the changes it undergoes. Chemists study the composition, structure, and properties of matter. They observe the changes that matter undergoes and measure the energy that is produced or consumed during these changes. Chemistry provides an understanding of many natural events and has led to the synthesis of new forms of matter that have greatly affected the way we live.Disciplines within chemistry are traditionally grouped by the type of matter being studied or the kind of study. These include inorganic chemistry, organic chemistry, physical chemistry, analytical chemistry, polymer chemistry, biochemistry, and many more specialized disciplines, e.g. radiochemistry, theoretical chemistry.Chemistry is often called "the central science" because it connects the other natural sciences such as astronomy, physics, material science, biology and geology.1.1. Classification of MatterMatter is usually defined as anything that has mass and occupies space. Mass is the amount of matter in an object. The mass of an object does not change. The volume of an object is how much space the object takes up.All the different forms of matter in our world fall into two principal categories: (1) pure substances and (2) mixtures. A pure substance can also be defined as a form of matter that has both definite composition and distinct properties. Pure substances are subdivided into two groups: elements and compounds. An element is the simplest kind of material with unique physical and chemical properties; it can not be broken down into anything simpler by either physical or chemical means. A compound is a pure substance that consists of two or more elements linked together in characteristic and definite proportions; it can be decomposed by a chemical change into simpler substances with a fixedmass ratio. Mixtures contain two or more chemical substances in variable proportions in which the pure substances retain their chemical identities. In principle, they can be separated into the component substances by physical means, involving physical changes. A sample is homogeneous if it always has the same composition, no matter what part of the sample is examined. Pure elements and pure chemical compounds are homogeneous. Mixtures can be homogeneous, too; in a homogeneous mixture the constituents are distributed uniformly and the composition and appearance of the mixture are uniform throughout. A solutions is a special type of homogeneous mixture. A heterogeneous mixture has physically distinct parts with different properties. The classification of matter is summarized in the diagram below:Matter can also be categorized into four distinct phases: solid, liquid, gas, and plasma. The solid phase of matter has the atoms packed closely together. An object that is solid has a definite shape and volume that cannot be changed easily. The liquid phase of matter has the atoms packed closely together, but they flow freely around each other. Matter that is liquid has a definite volume but changes shape quite easily. Solids and liquids are termed condensed phases because of their well-defined volumes. The gas phase of matter has the atoms loosely arranged so they can travel in and out easily. A gas has neither specific shape nor constant volume. The plasma phase of matter has the atoms existing in an excited state.1.2. Properties of MatterAll substances have properties, the characteristics that give each substance its unique identity. We learn about matter by observing its properties. To identify a substance, chemists observe two distinct types of properties, physical and chemical, which are closely related to two types of change that matter undergoes.Physical properties are those that a substance shows by itself, without changing into or interacting with another substance. Some physical properties are color, smell, temperature, boiling point, electrical conductivity, and density. A physical change is a change that does not alter the chemical identity of the matter. A physical change results in different physical properties. For example, when ice melts, several physical properties have changed, such as hardness, density, and ability to flow. But the sample has not changed its composition: it is still water.Chemical properties are those that do change the chemical nature of matter. A chemical change, also called a chemical reaction, is a change that does alter the chemical identity of the substance. It occurs when a substance (or substances) is converted into a different substance (or substances). For example, when hydrogen burns in air, it undergoes a chemical change because it combines with oxygen to form water.Separation of MixturesThe separation of mixtures into its constituents in a pure state is an important process in chemistry. The constituents of any mixture can be separated on the basis of their differences in their physical and chemical properties, e.g., particle size, solubility, effect of heat, acidity or basicity etc.Some of the methods for separation of mixtures are:(1)Sedimentation or decantation. To separatethe mixture of coarse particles of a solidfrom a liquid e.g., muddy river water.(2)Filtration. To separate the insoluble solidcomponent of a mixture from the liquidcompletely i.e. separating the precipitate(solid phase) from any solution.(3)Evaporation. To separate a non-volatilesoluble salt from a liquid or recover thesoluble solid solute from the solution.(4)Crystallization. To separate a solidcompound in pure and geometrical form.(5)Sublimation. To separate volatile solids,from a non-volatile solid.(6)Distillation. To separate the constituents of aliquid mixture, which differ in their boilingpoints.(7)Solvent extraction method. Organiccompounds, which are easily soluble inorganic solvents but insoluble or immisciblewith water forming two separate layers canbe easily separated.1.3 Atoms, Molecules and CompoundsThe fundamental unit of a chemical substance is called an atom. The word is derived from the Greek atomos, meaning “undivisible”or “uncuttable”.An atom is the smallest possible particle of a substance.Molecule is the smallest particle of a substance that retains the chemical and physical properties of the substance and is composed of two or more atoms;a group of like or different atoms held together by chemical forces. A molecule may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O).A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. The term is also used to refer to a pure chemical substance composed of atoms with the same number of protons. Until March 2010, 118 elements have been observed. 94 elements occur naturally on earth, either as the pure element or more commonly as a component in compounds. 80 elements have stable isotopes, namely all elements with atomic numbers 1 to 82, except elements 43 and 61 (technetium and promethium). Elements with atomic numbers 83 or higher (bismuth and above) are inherently unstable, and undergo radioactive decay. The elements from atomic number 83 to 94 have no stable nuclei, but are nevertheless found in nature, either surviving as remnants of the primordial stellar nucleosynthesisthat produced the elements in the solar system, or else produced as short-lived daughter-isotopes through the natural decay of uranium and thorium. The remaining 24 elements so are artificial, or synthetic, elements, which are products of man-induced processes. These synthetic elements are all characteristically unstable. Although they have not been found in nature, it is conceivable that in the early history of the earth, these and possibly other unknown elements may have been present. Their unstable nature could have resulted in their disappearance from the natural components of the earth, however.The naturally occurring elements were not all discovered at the same time. Some, such as gold, silver, iron, lead, and copper, have been known since the days of earliest civilizations. Others, such as helium, radium, aluminium, and bromine, were discovered in the nineteenth century. The most abundant elements found in the earth’s crust, in order of decreasing percentage, are oxygen, silicon, aluminium, and iron. Others present in amounts of 1% or more are calcium, sodium, potassium, and magnesium. Together, these represent about 98.5% of the earth’s crust.The nomenclature and their origins of all known elements will be described in Chapter 2.A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together in a defined spatial arrangement by chemical bonds. Compounds that exist as molecules are called molecular compounds. An ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds. Usually, the positively charged portion consists of metal cations and the negatively charged portion is an anion or polyatomic ion.The relative amounts of the elements in a particular compound do not change: Every molecule of a particular chemical substance contains acharacteristic number of atoms of its constituent elements. For example, every water molecule contains two hydrogen atoms and one oxygen atom. To describe this atomic composition, chemists write the chemical formula for water as H2O.The chemical formula for water shows how formulas are constructed. The formula lists the symbols of all elements found in the compound, in this case H (hydrogen) and O (oxygen). A subscript number after an element's symbol denotes how many atoms of that element are present in the molecule. The subscript 2 in the formula for water indicates that each molecule contains two hydrogen atoms. No subscript is used when only one atom is present, as is the case for the oxygen atom in a water molecule. Atoms are indivisible, so molecules always contain whole numbers of atoms. Consequently, the subscripts in chemical formulas of molecular substances are always integers. We explore chemical formulas in greater detail in Chapter 2.The simple formula that gives the simplest whole number ratio between the atoms of the various elements present in the compound is called its empirical formula. The simplest formula that gives the actual number of atoms of the various elements present in a molecule of any compound is called its molecular formula. Elemental analysis is an experiment that determines the amount (typically a weight percent) of an element in a compound. The elemental analysis permits determination of the empirical formula, and the molecular weight and elemental analysis permit determination of the molecular formula.1.4. Numbers in Physical Quantities1.4.1. Measurement1.Physical QuantitiesPhysical properties such as height, volume, and temperature that can be measured are called physical quantity. A number and a unit of defined size are required to describe physical quantity, for example, 10 meters, 9 kilograms.2.Exact NumbersExact Numbers are numbers known withcertainty. They have unlimited number of significant figures. They arise by directly counting numbers, for example, the number of sides on a square, or by definition:1 m = 100 cm, 1 kg = 1000 g1 L = 1000 mL, 1 minute = 60seconds3.Uncertainty in MeasurementNumbers that result from measurements are never exact. Every experimental measurement, no matter how precise, has a degree of uncertainty to it because there is a limit to the number of digits that can be determined. There is always some degree of uncertainty due to experimental errors: limitations of the measuring instrument, variations in how each individual makes measurements, or other conditions of the experiment.Precision and AccuracyIn the fields of engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements results to its actual (true) value. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which repeated measurements under unchanged conditions show the same results. Although the two words can be synonymous in colloquial use, they are deliberately contrasted in the context of the scientific method.A measurement system can be accurate but not precise, precise but not accurate, neither, or both. A measurement system is called valid if it is both accurate and precise. Related terms are bias (non-random or directed effects caused by a factor or factors unrelated by the independent variable) and error(random variability), respectively. Random errors result from uncontrolled variables in an experiment and affect precision; systematic errors can be assigned to definite causes and affect accuracy. For example, if an experiment contains a systematic error, then increasing the sample size generally increases precision but does not improve accuracy. Eliminating the systematic error improves accuracy but does not change precision.1.4.2 Significant FiguresThe number of digits reported in a measurement reflects the accuracy of the measurement and the precision of the measuring device. Significant figures in a number include all of the digits that are known with certainty, plus the first digit to the right that has an uncertain value. For example, the uncertainty in the mass of a powder sample, i.e., 3.1267g as read from an “analytical balance” is 0.0001g.In any calculation, the results are reported to the fewest significant figures (for multiplication and division) or fewest decimal places (addition and subtraction).1.Rules for deciding the number of significantfigures in a measured quantity:The number of significant figures is found by counting from left to right, beginning with the first nonzero digit and ending with the digit that has the uncertain value, e.g.,459 (3) 0.206 (3) 2.17(3) 0.00693 (3) 25.6 (3) 7390 (3) 7390. (4)(1)All nonzero digits are significant, e.g., 1.234g has 4 significant figures, 1.2 g has 2significant figures.(2)Zeroes between nonzero digits aresignificant: e.g., 1002 kg has 4 significantfigures, 3.07 mL has 3 significant figures.(3)Leading zeros to the left of the first nonzerodigits are not significant; such zeroes merelyindicate the position of the decimal point:e.g., 0.001 m has only 1 significant figure,0.012 g has 2 significant figures.(4)Trailing zeroes that are also to the right of adecimal point in a number are significant:e.g., 0.0230 mL has 3 significant figures,0.20 g has 2 significant figures.(5)When a number ends in zeroes that are notto the right of a decimal point, the zeroes arenot necessarily significant: e.g., 190 milesmay be 2 or 3 significant figures, 50,600calories may be 3, 4, or 5 significant figures.The potential ambiguity in the last rule can be avoided by the use of standard exponential, or "scientific" notation. For example, depending onwhether the number of significant figures is 3, 4, or 5, we would write 50,600 calories as:5.06 × 104 calories (3 significant figures)5.060 ×104calories (4 significant figures), or5.0600 × 104 calories (5 significant figures).2.Rules for rounding off numbers(1)If the digit to be dropped is greater than 5,the last retained digit is increased by one.For example, 12.6 is rounded to 13.(2)If the digit to be dropped is less than 5, thelast remaining digit is left as it is. Forexample, 12.4 is rounded to 12.(3)If the digit to be dropped is 5, and if anydigit following it is not zero, the lastremaining digit is increased by one. Forexample, 12.51 is rounded to 13.(4)If the digit to be dropped is 5 and isfollowed only by zeroes, the last remainingdigit is increased by one if it is odd, but leftas it is if even. For example, 11.5 is roundedto 12, 12.5 is rounded to 12.This rule means that if the digit to be dropped is 5 followed only by zeroes, the result is always rounded to the even digit. The rationale is to avoid bias in rounding: half of the time we round up, half the time we round down.3.Arithmetic using significant figuresIn carrying out calculations, the general rule is that the accuracy of a calculated result is limited by the least accurate measurement involved in the calculation.(1) In addition and subtraction, the result is rounded off to the last common digit occurring furthest to the right in all components. Another way to state this rules, is that, in addition and subtraction, the result is rounded off so that it has the same number of decimal places as the measurement having the fewest decimal places. For example,100 (assume 3 significant figures) + 23.643 (5 significant figures) = 123.643,which should be rounded to 124 (3 significant figures).(2) In multiplication and division, the resultshould be rounded off so as to have the same number of significant figures as in the component with the least number of significant figures. For example,3.0 (2 significant figures ) ×12.60 (4 significant figures) = 37.8000which should be rounded off to 38 (2 significant figures).1.4.3 Scientific NotationScientific notation, also known as standard form or as exponential notation, is a way of writing numbers that accommodates values too large or small to be conveniently written in standard decimal notation.In scientific notation all numbers are written like this:a × 10b("a times ten to the power of b"), where the exponent b is an integer, and the coefficient a is any real number, called the significant or mantissa (though the term "mantissa" may cause confusion as it can also refer to the fractional part of the common logarithm). If the number is negative then a minus sign precedes a (as in ordinary decimal notation).In standard scientific notation the significant figures of a number are retained in a factor between 1 and 10 and the location of the decimal point is indicated by a power of 10. For example:An electron's mass is about 0.00000000000000000000000000000091093822 kg. In scientific notation, this is written 9.1093822×10−31 kg.The Earth's mass is about 5973600000000000000000000 kg. In scientific notation, this is written 5.9736×1024 kg.1.5 Units of Measurement1.5.1 Systems of Measurement1.United States Customary System (USCS)The United States customary system (also called American system) is the most commonly used system of measurement in the United States. It is similar but not identical to the British Imperial units. The U.S. is the only industrialized nation that does not mainly use the metric system in its commercial and standards activities. Base units are defined butseem arbitrary (e.g. there are 12 inches in 1 foot)2.MetricThe metric system is an international decimalized system of measurement, first adopted by France in 1791, that is the common system of measuring units used by most of the world. It exists in several variations, with different choices of fundamental units, though the choice of base units does not affect its day-to-day use. Over the last two centuries, different variants have been considered the metric system. Metric units are universally used in scientific work, and widely used around the world for personal and commercial purposes. A standard set of prefixes in powers of ten may be used to derive larger and smaller units from the base units.3.SISI system (for Système International) was adopted by the International Bureau of Weights and Measures in 1960, it is a revision and extension of the metric system. Scientists and engineers throughout the world in all disciplines are now being urged to use only the SI system of units.1.5.2 SI base unitsThe SI is founded on seven SI base units for seven base quantities assumed to be mutually independent, as given in Table 1.1.Table 1.1 SI Base Physical Quantities and UnitsU n i tN a m e UnitSymbolBaseQuantityQuantitySymbolDimensionSymbolm m l l Le t e r e n g t hk i lo g r a m kgmassm Ms ec o nd stimet Ta mp e r e AelectriccurrentI Ik el v i n KthermodynTΘm i ct e m p e r a t u r em o l e molamountofsubstancen Nc an d e l a cdluminousIvJntensity1.5.3 SI derived unitsOther quantities, called derived quantities, aredefined in terms of the seven base quantities via asystem of quantity equations. The SI derived unitsfor these derived quantities are obtained from theseequations and the seven SI base units. Examples ofsuch SI derived units are given in Table 1.2, where itshould be noted that the symbol 1 for quantities ofdimension 1 such as mass fraction is generallyomitted.Table 1.2 SI Derived Physical Quantities and(symbol) Unit(symbol)UArea (A) squaremeterm V olume (V) cubicmeterm Density (ρ) kilogramper cubicmeterkVelocity (u) meterpersecondmPressure (p) pascal(Pa)kEnergy (E) joule (J) (k Frequency (ν) hertz(Hz)1Quantity of electricity (Q) coulomb(C)AElectromotive force (E) volt (V) (kmsForce (F) newton(N)kFor ease of understanding and convenience, 22SI derived units have been given special names andsymbols, as shown in Table 1.3.Table 1.3 SI Derived Units with special names andsymbolsD e r i v e dq u a n t i t y SpecialnameSpecialSymbolExpressionintermsofotherSIunitsSIbaseunitsp r r ml a n ea n g l e adianad·m-1=1s o l i da n g l e steradiansrm2·m-2=1f r e q u e n c y hertzHzs-1f o r c e newtonN m·kg·s-2p p P N mr e s s u r e ,s t r e s s ascala/m21·kg·s-2e n e r g y ,w o r k ,q u a n t i t yo fh e a jouleJ N·mm2·kg·s-2p o w e r ,r a d i a n tf l u x wattW J/sm2·kg·s-3e l e c t r i cc h a r g e q u a n t i t y coulombC s·Afe l e c t r i c i t ye l e c t r i cp o t e n t i a l ,p o t e n t i a l voltV W/Am2·kg·s-3·A-1i f f e r e n c e ,e l e c t r o m o t i v ef o r c ec a p a c i t a n c e faradF C/Vm-2·kg-1·s 4·A 2e l e c t r i cr e s i s t a n c e ohmΩV/Am2·kg·s-3·A-2e l e c t r i cc o nd u c t a n c siemensS A/Vm-2·kg-1·s2·Aem a g n e t i cf l u x weberWbV·sm2·kg·s-2·A-1m a g n e t i cf l u xd e n s i t y teslaT Wb/m2kg·s-2·A-1i n d henH Wb/m2u c t a n c e ryA ·kg·s-2·A-2C e l s i u st e m p e r a t u r e degreeCelsius°CKl u m i n o u s lumenlmcd·srcd·srl u xi l l u m i n a n c e luxlxlm/m2m-2·cd·sra c t i v i t y( o far a d i o n u c l i d e becquerelBqs-1a b s o r b e dd o se ,s p e c i f i ce n e r g y( i m p a r t e d ) ,grayGyJ/kgm2·s-2e r m ad o s ee q u i v a l e n t ,e ta l .sievertSvJ/kgm2·s-2c a t a l y t i ca c t i v i katalkats-1·molyCertain units that are not part of the SI are essential and used so widely that they are accepted by the CIPM (Commission Internationale des Poids Et Mesures) for use with the SI. Some commonly used units are given in Table 1.4.Table 1.4 Non-SI units accepted for use with theSIN a m e SymbolQuantityEquivalentSIunitmi n u t e mintime1min=6sho u r htime1h6min=36s da y dtime1d=24h=144min=864sdegreeo fa r c °planeangle1°=(π/18)radm i n u t eo fa r c ′planeangle1′=(1/6)°=(π/18radsecondo fa r c ″planeangle1″=(1/6)′=(1/36)°=(π/648)rdhect a r e haarea1ha=1a=1m²l i t r e lorLvolume1l=1dm3=.1m3ton n e tmass1t=13kg=1MgThe 20 SI prefixes used to form decimal multiples and submultiples of SI units are given in Table 1.5.Table 1.5 SI PrefixesF a c t o r NameSymbolFactorNameSymbol1 0 24yottaY 1-1decid1 0 21zettZ 1-2centc。

翻译原文

Comparison of Microstructure and Mechanical Propertiesof AZ91D Alloy Formed by Rheomoldingand High-Pressure Die Casting()The microstructure and mechanical properties of AZ91D alloy thin-wall parts produced by the 组织 AZ91D镁合金薄壁零件的机械性能产生rheomolding(RM) process were investigated and compared with the same alloy formed by conventional研究传统的high pressure die casting (HPDC). The results indicate that the RM process is able to get such AZ91D 高压压铸parts in which a1-Mg with average size of 27.36 l m are spherical and uniformly distributed in the球形均匀分布matrix, and the matrix is a mixture of numerous fine a2-Mg and intermetallic b-Mg17Al12. High mechanical 矩阵机械properties including ultimate tensile strength (UTS) of 270 MPa, yield strength (YS) of 169 MPa, 极限抗拉强度屈服强度elongation of 7.1%,and Vickers hardness of 102 are obtained in parts formed by RM due to the fine维氏硬度and uniform microstructure and less porosities. Compared with HPDC, the UTS, YS, elongation, and 组织均匀，气孔少压铸hardness of RM AZ91D are increased by 14.4, 9.7, 86.8, and 21.4%, respectively. The solidified grains凝固晶粒in RM AZ91D alloy show a smaller aluminum gradient than that in HPDC. This indicates that the较小铝梯度solidification of the RM AZ91D is closer to equilibrium..1. IntroductionMg-alloys, with a number of desirable properties including light weight, high specific strength理想性能比强度and specific stiffness,excellent damping property and well castability, are thus very 比刚度优良阻尼性能铸造性能attractive for the applications in 3C (computers, communications,and consumer electronics) andautomotive industries (Ref1-4). Over the past decades, with the rapid expansion of Mg-alloyapplications, large-scale thin-wall parts have been developed and implemented by taking full大型薄壁零件实施advantage of high-pressure die casting (HPDC) (Ref 5). However, HPDC partshave high-gas porosity levels, due primarily to the entrapment of air or gas in the melt during 高瓦斯孔隙度空气滞留the high-speed filling of turbulent molten metal into the cavity. The porosities can腔孔隙度severely degrade mechanical properties by acting as local stress concentrators. They also lead 降解浓缩机to problems during heat treatment or welding, where heating causes the expansion of gas in pores,热处理或焊接扩展and result in bubbling and dimensional changes (Ref 6). Also,repositories may have an adverse尺寸变化effect on the corrosion resistance of Mg-alloys (Ref 7).耐腐蚀性In order to solve these problems and meet demands of future applications, alternative castingprocess is developing. Semisolid metal (SSM) processing is a promising manufacturing半固态金属制造route that is capable of producing castings with a high level of quality. SSM processing involves 路线casting a semisolid slurry that exhibits non-turbulent or thixotropic flow behavior (Ref 8-10).铸造半固态浆料展品非湍流触变流动行为Semisolid cast alloys offer several advantages over their HPDC counterparts. For example, the 半固态铸造fraction of pores is lower owing to the laminar mold-filling process that results in less孔隙分数层流充型过程entrapped air (Ref 11, 12). SSM techniques are divided into two categories: thixo (thixomolding 截留空气类别触变(TM) and thixocasting (TC)) and rheo (rheomolding (RM) and rheocasting (RC)) processes.触变铸造流变流变铸造However, TC and RC are difficult to form thin-wall parts for the poor controllability of the melt temperature in chamber.Presently, the only commercially available SSM technology forthin-wall Mg-alloy parts is TM. Though TM has made a great progress and produced the parts withbetter strength and ductility, there still exist many shortcomings, such as poor wear resistance耐磨性差and short service life of the screw and the cylinder liner which are key components of thethixomolder (Ref 13).Moreover, using Mg-alloy particles as raw materials directly results in原材料the increase of production cost (Ref 13, 14).生产成本2. Experiment Procedures2.1 MaterialsCommercial AZ91D alloy was used in this investigation, for which the reported solidus and liquidus temperatures are 468 and 598 C, respectively. The chemical composition of theAZ91D alloy is 9.45% Al, 0.66% Zn, 0.20% Mn, 0.036% Si,0.005% Cu, 0.001% Ni, and Mg balance (by weight).2.2 The RM ProcessThe RM process is an innovative one-step SSM processing technique which, through the use创新一步半固态加工技术of LSP technology, can manufacture near-net shape parts with high integrity directly from liquid制造近净成形件完整性液体alloy without turbulence or gas entrapment.Figure 1 shows the schematic of the NISSEI FMg220-16HM 湍流或气体滞留示意图rheomolder which is composed of melting barrel, blunt gas injection pipe, storage tank, nozzle, injection system, etc.The melting barrel is suitable to accommodate rod-shaped materials with the size of U 609300 熔化筒容纳棒状材料mm, which are melted by heating components. The temperatures of storage tank and融化加热元件储存罐material temperature control barrel are considered as the melt temperature and pouringtemperature, respectively. The semisolid slurry is prepared in injection cylinder, which mainly半固态浆料喷油缸consists of the nozzle, runner, and material measurement room.The injection system is used to 喷嘴，流道和材料测量室注入系统inject the slurry into the mold cavity with high pressure and speed, and the forming parts are 浆phone covers (110960 mm) with the thickness of 0.8 mm.In the RM process, specific parameters were as follows: the melt temperature of 670 C,具体参数pouring temperature of 630 and 610 C, cylinder temperature of 570 C, injection pressure注射压力Of 35 MPa, injection velocity of 1.8 m/s, and mold temperature of 250 C. For the purpose ofcomparison, similar AZ91D phone covers (120955 mm) with a section thickness of 0.8 mm weredie casting on a 400-ton cold chamber HPDC machine. During HPDC, pouring temperature of 630 压铸400吨冷室压铸机。

Al-3Y-2B中间合金对Al-20Si铸态组织和力学性能的影响

第38卷第3期2024年5月山东理工大学学报(自然科学版)Journal of Shandong University of Technology(Natural Science Edition)Vol.38No.3May 2024收稿日期:20230421基金项目:山东省自然科学基金项目(ZR2020ME108);泰安市科技创新重大专项项目(2021ZDZX017)第一作者:王广雨,男,156****1356@;通信作者:许荣福,男,13559@文章编号:1672-6197(2024)03-0065-06Al -3Y -2B 中间合金对Al -20Si 铸态组织和力学性能的影响王广雨1,徐勇1,冯以盛1,裴栋梁2,韩玉秀1,许荣福1(1.山东建筑大学材料科学与工程学院,山东济南250101;2.山东泰开精密铸造有限公司,山东泰安271000)摘要:研究了Al -3Y -2B 中间合金对过共晶Al -20Si 二元合金铸态组织及性能的影响规律,基于冷却曲线分析(CCA )方法,测得了Al -20Si 二元合金中加入Al -3Y -2B 中间合金前后的冷却曲线㊂实验结果表明:Al -20Si 合金熔体加入1.0%的Al -3Y -2B 中间合金后,初生硅的生成温度降低约13ħ;铸态组织的初生硅平均尺寸由110μm 减小到33μm ,初生硅形貌由粗大的多边形结构转变为尺寸细小的板状结构;共晶硅形貌由细长针状转变为短针状和短棒状;铸态合金的伸长率(EL )由1.62%提升到1.98%,极限抗拉强度(UTS )由120MPa 提升到162MPa ㊂Al -3Y -2B 的添加量为0.5%时,组织中的初生硅和共晶硅被很好的细化;Al -3Y -2B 的添加量提高到1.0%时,Al 基体中开始出现脆性相,影响合金的机械性能㊂关键词:过共晶铝硅合金;中间合金;变质处理;晶粒细化;热分析中图分类号:TG146.21文献标志码:AEffect of Al -3Y -2B master alloy on the microstructureand mechanical properties of Al -20Si castingWANG Guangyu 1,XU Yong 1,FENG Yisheng 1,PEI Dongliang 2,HAN Yuxiu 1,XU Rongfu 1(1.School of Materials Science and Engineering,Shandong Jianzhu University,Jinan 250101,China;2.Shandong Taikai Precision Casting Company Limited,Taiᶄan 271000,China)Abstract :The influence of Al -3Y -2B master alloy on the as-cast microstructure and properties of hyper-eutectic Al -20Si binary alloy were studied.Based on the cooling curve analysis (CCA)method,the cooling curve before and after the addition of Al -3Y -2B master alloy in Al -20Si binary alloy was meas-ured.The experimental results showed that the primary phase generation temperature decreased by about 13ħwhen 1.0%Al -3Y -2B master alloy was added to Al -20Si alloy melt.The average size of prima-ry silicon decreased from 110μm to 33μm,and the morphology of primary silicon changed from coarse polygonal structure to fine plate structure.The morphology of eutectic silicon changed from the slender needles to short needles and rods.The elongation (EL)of the as-cast alloy increased from 1.62%to 1.98%,and the ultimate tensile strength (UTS)increased from 120MPa to 162MPa.When the amount of Al -3Y -2B was 0.5%,the primary silicon and eutectic silicon were refined well.When the additionof Al -3Y -2B increased to 1.0%,the brittle phase began to appear in Al matrix,which affected the me-chanical properties of the alloy.Keywords :hypereutectic Al -Si alloy;master alloy;modification;grain refinement;thermal analysis㊀㊀㊀Al-Si合金因其优异的耐腐蚀性㊁较高的热稳定性和优异的机械性能而在许多工业领域中得到应用㊂过共晶Al-Si合金的组织主要由初生硅㊁共晶硅和α-Al三种相组成[1],粗大的多边形初生硅颗粒严重破坏基体的连续性,降低合金的延展性;另外,大块的初生硅相具有很高的硬度,在机加工中会加快刀具损耗,提高生产成本[2],所以细化初生硅对提高过共晶Al-Si合金的性能起到决定性的作用㊂目前,细化初生硅的方法主要有变质处理㊁快速凝固及外加物理场等[3-4]㊂变质处理是改变初生硅形态最有效㊁应用最广的一种方法[5],研究人员在变质处理改善合金力学性能方面已经做了相当多的工作㊂在较低凝固速率下锶的中间合金可以很好地变质细化过共晶Al-Si合金组织,在提高合金力学性能方面强于钠盐变质合金,但是锶的中间合金和钠盐的变质都只对共晶硅有效[6-7]㊂为了细化过共晶Al-Si合金中的初生硅[8-9],研究人员发现磷(P)可以细化初生硅,磷对初生硅的变质效果好,细化效果稳定[10]㊂后来,研究人员发现稀土(RE)可以细化初生硅和共晶硅,是一种优良的Al-Si合金变质剂,并且RE对共晶硅的变质效果比对初生硅的变质效果明显[11-13]㊂稀土钇(Y)对过共晶Al-Si合金中的硅相有明显的变质效果,有研究发现稀土钇可以同时细化初生硅和共晶硅[14]㊂早期研究已经证明Al-Y-B系中间合金对铝硅合金的变质细化作用,不溶性YB2颗粒被认为是初生硅和硅形态变质的有效核[15]㊂据报道,冷却曲线分析(CCA)是了解添加晶粒细化剂效果的一种简单而有用的方法㊂在研究铝合金凝固方面,CCA有许多应用,可以用来测定孕育程度㊁晶粒细化㊁潜热和固相率等信息[16-17]㊂在CCA分析中,热电偶用于记录凝固过程中样品的温度变化,然后得到合金凝固过程中的冷却曲线,从冷却曲线及其一阶导数中可以获得孕育程度等不同的参数[18-19]㊂本文以Al-20Si二元合金为研究对象,研究Al-3Y-2B中间合金对Al-20Si合金铸态组织细化效果及其对力学性能的影响规律,利用XRD和SEM表征Al-3Y-2B中间合金的组织状态,利用CCA方法表征合金孕育前后的凝固过程,利用光学显微镜(OM)表征铸态组织状态,利用CMT4202电子实验机进行力学性能测试㊂1㊀实验过程本研究中使用工业纯铝(质量分数99.7%)㊁工业纯硅(质量分数99.6%)㊁金属钇(质量分数99.0%)㊁Al-3Y-2B中间合金和Al-P中间合金等材料进行合金熔配㊂首先在电阻炉中熔配实验所用的Al-20Si二元合金,然后将一定质量的Al-3Y-2B中间合金㊁Al-3P中间合金分别添加到Al-20Si 合金熔体中,保温处理15min,并用六氯乙烷(C2Cl6)进行除气除渣处理㊂清理氧化渣后,将合金熔体浇入已预热至200ħ的石墨坩埚中进行凝固和测温㊂图1是本实验所用的测温装置示意图,K型热电偶位于坩埚中心,偶头距离坩埚顶部35mm,温度数据采集系统以10Hz的频率进行记录㊂本实验的力学性能试样是将合金熔体浇入预热至200ħ的金属模具中,加工成标准的抗拉强度试样,根据ASTM B557标准在室温下在CMT4204电子实验机上进行实验㊂从热电偶尖端所在位置横向剖切样品获得金相试样,按照金相标准进行试样的制备,使用OM进行表征㊂图1㊀测量Al-20Si熔体冷却曲线的实验装置示意图2㊀结果和讨论2.1㊀对Al-3Y-2B中间合金组织的表征图2是Al-3Y-2B中间合金的XRD检测结果㊂从图2可以得到,在Al-3Y-2B中间合金中检测到α-Al和YB2的衍射峰,YB2是Y和B相互作用形成的化合物,前期工作证明,这种YB2在变质时可以充当初生硅和共晶硅形核的异质核心[15]㊂图366山东理工大学学报(自然科学版)2024年㊀是对Al -3Y -2B 进行SEM 分析的结果㊂从图3(a)可以看到,Al -3Y -2B 组织中有两种相,其中深灰色的是α-Al 相,浅色是YB 2,这种YB 2相在基体中呈现为不规则板片状和长条状㊂图3(b)是YB 2的微观形貌,可以看到这种钇硼化合物表面有棱边和尖角,大小不均匀且呈团簇状,晶粒尺寸在2~9μm 之间㊂图2㊀Al -3Y -2B 中间合金的XRD表征结果(a)Al -3Y -2B中间合金微观形貌(b)YB 2相微观形貌图3㊀Al -3Y -2B 的SEM 图片2.2㊀冷却曲线图4是添加不同中间合金的Al -20Si 合金冷却曲线㊂通过图4可以看到,加入不同变质剂,初生硅的形核温度不同㊂加入Al -P 中间合金后初生硅的形核温度出现明显的升高,这说明Al -P 的加入改变了合金初生相的生成温度,而初生硅生成温度升高意味着有更多的初生硅生成并释放出更多的潜热;而且,中间合金加入后为母材合金引入了大量的异质核心粒子,有利于初生硅的形核和长大㊂添加Al -3Y -2B 后初生硅的形核温度降低约13ħ,这与Al -P 或Al -Si -Fe 中间合金的变质效果类似[20-21],说明在加入含有YB 2的中间合金后也可以像添加Al -P 中间合金那样改变初生硅的形核温度,这是因为加入Al -3Y -2B 中间合金为初生硅引入了YB 2作为形核的异质核心,有更多的初生硅形核和长大,使初生硅生成温度发生变化㊂从图4中的冷却曲线可以看到,加入Al -3Y -2B 中间合金后,共晶生长温度提高了1.5ħ㊂共晶生长温度用于评估Al -Si 熔体中共晶硅的变质程度[17-18]㊂经过分析发现,即使共晶生长温度升高,合金中的共晶硅仍保持变质后的形态,与纯锶变质后合金的情况相同,这意味着共晶生长温度升高也不会导致变质作用减弱,说明硅的形态和共晶生长温度之间不存在直接的关系[22-23];相反,共晶生长温度的升高说明Al -3Y -2B 对共晶硅有细化作用,添加Al -3Y -2B 中间合金为共晶硅引入了形核基底,增加了共晶硅的形核频率,根据经典形核理论,共晶硅的大小取决于形核频率,随着形核频率的增加,共晶硅得到细化[24]㊂图4㊀添加不同中间合金的Al -20Si 合金冷却曲线2.3㊀铸态组织及性能测试基于相同的实验条件,考察添加0.5%和1.0%的Al -3Y -2B 对过共晶Al -Si 合金中初生硅和共晶76第3期㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀王广雨,等:Al -3Y -2B 中间合金对Al -20Si 铸态组织和力学性能的影响硅的变质作用㊂图5显示了添加不同中间合金的Al-20Si二元合金的典型铸态组织㊂图6是经不同中间合金变质后初生硅晶粒尺寸对比图㊂图5(a)是未添加任何中间合金的Al-20Si的金相图片㊂从图中可以看到,未变质的初生硅晶粒较大,呈多面体和板块状分布在基体上,平均晶粒尺寸约为110μm㊂图5(b)是加入Al-P中间合金后的金相组织,组织中已经看不到较大尺寸的晶粒,经变质后晶粒尺寸分布在较小的范围,初生硅晶粒与未变质的晶粒相比明显变小,初生硅得到细化㊂图5(c)是加入0.5%Al-3Y-2B变质后的金相图片,从图中可以看到组织中尺寸较小的初生硅晶粒数量增多,初生硅被细化,大尺寸的块状初生硅数量减少,变质效果较好㊂图5(d)是经1.0%Al-3Y-2B变质后的金相图,结合图6可以得出,与添加0.5%的Al-3Y-2B 变质结果相比,初生硅晶粒没有继续减小的趋势,初生硅晶粒甚至有增大倾向,这说明添加1.0%的Al-3Y-2B并没有使初生硅进一步细化㊂由图6可以看到,与未添加变质剂的合金相比,Al-3Y-2B的变质细化效果明显,初生硅晶粒的平均尺寸约30μm [图5(c)和(d)]㊂与添加了Al-P中间合金的Al-20Si相比,经过Al-3Y-2B变质的初生硅晶粒尺寸和形态更均匀,此外,分析发现Al-3Y-2B中间合金的添加量对研究范围内的变质结果几乎没有影响[图5(c)和(d)],说明Al-3Y-2B中间合金在低添加量下有效㊂图5(a)是未经过变质处理的Al-20Si金相组织照片㊂从图中可以看到,未变质的共晶硅呈细长针状,尺寸长短不一,杂乱的分布在Al基体上,部分共晶硅的取向具有一定的方向性,一些区域的共晶硅近似平行生长,这些细长针状的共晶硅会割裂基体,严重削弱合金的力学性能㊂图5(b)是经过Al-P中间合金变质后的共晶硅金相图片㊂从图中可以看到,共晶硅一部分呈针状,大部分变为尺寸较小的短棒状,而且在基体中分布的更均匀㊂图5(c)和(d)是分别添加0.5%和1.0%变质的Al-3Y-2B 中间合金的金相组织图㊂从图中可以看到,共晶硅形貌和大小均发生了明显的变化,共晶硅由未变质时的长针状变为短针状和短棒状,均匀分布在Al基体上,这说明Al-3Y-2B细化共晶硅的能力强于Al -P中间合金㊂从图5(c)和(d)可以看到,随着Al-3Y-2B的添加,Al-20Si合金基体上出现大量的白条状和板片状的富钇相㊂从对Al-3Y-2B的XRD和SEM表征结果可以得出,这种富钇相是YB2相㊂Al-3Y-2B的添加量为0.5%时,富钇相较少,Al-3Y-2B添加量越多富钇相也随之增多㊂由文献可知,这种相为脆性相,其熔点和硬度比较高,可以作为初生硅和共晶硅的形核基底,但是富钇相耐腐蚀性较差,容易在凝固过程中形成裂纹和孔洞,从而削弱合金性能㊂从图5(d)可以看到富钇相上出现了黑色的孔洞㊂添加Al-3Y-2B可以细化晶粒,改变初生硅和共晶硅的形态,提高合金的性能,但是过量加入Al-3Y-2B会生成大量的富钇相,对材料的物理和机械性能产生不利的影响㊂㊀㊀(a)未添加(b)添加1.0%Al-P㊀(c)添加0.5%Al-3Y-2B(d)添加1.0%Al-3Y-2B 图5㊀添加了不同中间合金的Al-20Si试样铸态组织图6㊀Al-20Si合金初生硅晶粒尺寸图7是不同添加量的Al-3Y-2B对过共晶Al-Si合金力学性能的影响㊂由图7可以看出,添加Al -3Y-2B后,Al-20Si合金的极限抗拉强度(UTS)和伸长率(EL)都明显提高,未添加Al-3Y-2B的Al-20Si合金的极限抗拉强度约为120ʃ8MPa,当Al-3Y-2B添加量分别为0.5%和1.0%时,合金的极86山东理工大学学报(自然科学版)2024年㊀限抗拉强度分别增加到158ʃ6MPa 和162ʃ7MPa;对比添加中间合金前后的伸长率,Al -20Si 的伸长率从1.62ʃ0.3%分别提高到2.10ʃ0.2%和1.98ʃ0.4%㊂在Al -20Si 中添加Al -3Y -2B 中间合金可以提高过共晶Al -Si 二元合金的力学性能㊂图7㊀Al -20Si 合金的力学性能下面主要探讨不同形态初生硅和共晶硅的生长机理,说明Al -3Y -2B 对初生硅和共晶硅生长方式的影响并进行具体的理论分析㊂过共晶Al -Si 合金中初生硅的不同形态受其不同的生长条件影响,初生硅的形态主要呈板状㊁星形及多面体状等㊂张承甫等[25]研究了Al -Si 合金中八面体硅的生长方式,五瓣星形的初生硅经常出现在硅含量较高的Al -Si 合金中,凝固速度对这种形态初生硅的形成也有一定的影响㊂一般认为多重孪晶决定了这种初生硅的形态,在液态金属中五个四面体之间形成的孪晶变为十面体后转变为这种五瓣星形的初生硅㊂张蓉等[26]研究了Al -Si 合金中的初生硅的生长方式和机理,结果发现硅相在重熔过程中并未全部溶解,而是成为初生硅形核长大的核心,在凝固结晶时,初生硅的形状与未熔解的硅颗粒之间存在一定的对应关系㊂初生硅的生长机制有两种,即孪晶凹谷机制(TPRE)和台阶机制两种生长方式,而其他因素如温度和晶体的外界生长环境等决定硅的最终形态㊂如果金属液的温度升高,初生硅在凝固时会呈现星形或树枝状从而取代之前的多面体状㊂过共晶Al -Si 合金中共晶硅的形态分布对提高合金的性能有着很大的影响,所以研究共晶硅的变质机理对优化合金组织有着重要的意义㊂上面提及加入Al -3Y -2B 中间合金后,共晶硅的晶粒从之前的长针状变为短棒状㊁短针状和点状,这表示共晶硅发生了球化现象㊂经过中间合金变质后共晶硅的生长方式发生了很大的变化,生长方式变为非平稳态,从而导致分枝增多,同时,晶体内部的缺陷增大且均为孪晶中的缺陷,这些因素都会导致共晶硅加快发生球化㊂对于共晶硅的变质机理,主要的解释有孪晶凹谷机制(TPRE)和台阶机制㊂用孪晶机制来解释,此理论认为在共晶硅的结晶区域是孪晶凹谷,经过富钇相变质,液态合金中的孪晶凹谷处吸附和富集了大量的Y 原子,阻碍和减缓了Si 原子四面体或Si 原子的生长速度,使其长大受到抑制,所以硅晶体长大后的形态被改变㊂硅晶体的生长方向被改变是由于稀土阻碍了孪晶凹谷沿[100]㊁[110]㊁[112]等晶向生长,硅晶体也由此发生分化;并且,Y 原子并非阻碍整个凹谷,而是优先吸附在凹谷内的位错㊁层错等缺陷处,分割了Si 晶体原来的片状结构,这些因素都促使Si 晶体由片状变成等轴断面的弯曲纤维状,共晶硅生长机制的变化导致硅形态发生变化㊂Al 和Si 的共晶结晶属于非小平面与非小平面的共生生长,因为Si 结晶的界面最光滑㊁阻力最小,Si 在结晶时会优先形核,而A1相的生长速度远远慢于Si 相,Si 相各向异性的晶体结构使其长大成不同的形态,常见的有板条状㊁多面体或者分散的针状㊂在加入Al -3Y -2B 变质后,Y 相在孪晶处的富集阻碍了Si 相的长大,使两相的生长方式发生极大的改变,几乎变为共同非小平面的生长,所以会形成细小的共晶硅组织㊂3㊀结论本文制备了一种新型的Al -3Y -2B 中间合金,并与通用的Al -P 中间合金对比,研究了Al -3Y -2B 对Al -20Si 二元合金铸态组织和力学性能的影响㊂根据实验结果和讨论,得出了以下结论:1)Al -3Y -2B 中间合金能够同时变质共晶硅和初生硅㊂Al -3Y -2B 在低添加量下效果明显,过多添加Al -3Y -2B 会在基体上生成白条状或点状的脆性相,影响合金的力学性能㊂2)添加Al -3Y -2B 可以提高Al -20Si 合金中硅的形核频率和共晶生长温度,降低初生硅的形核温度;另外,添加Al -3Y -2B 后,Al -20Si 的极限抗拉强度(UTS)和伸长率(EL)都得到提高㊂参考文献:[1]朱运茂.新型AlP -Al 2O 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3 Results and discussions
Zn2TiO4 ZnTiO3
Intensity (a.u.)
(a)
(b)
20
30
40
50
60
70
2θ (deg)
Fig. 2 XRD patterns for calcined powder at 850 °C (a) and sintered samples with CVB addition at 850 °C (b)
Z. Yue (*) : J. Yan : F. Zhao : Z. Gui : L. Li
State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, People’s Republic of China e-mail: y Nhomakorabeaezhx@
In the present works, some low-melting compounds of CuO-V2O5-Bi2O3 (CVB) were added to lower sintering temperature of ZnTiO3 ceramics, so as to suppress the decomposition of ilmenite phase. The phase relationship and dielectric properties as a function of sintering temperature and addition amount were investigated.

烧结前后xrd衍射峰

烧结前后xrd衍射峰The X-ray diffraction (XRD) technique is a powerful tool for analyzing the crystallographic structure of materials. It is commonly used to study the phase composition and microstructure of materials before and after sintering. Sintering is a process in which powdered materials are compacted and heated to form a solid mass without melting. This process can significantly alter the crystallographic structure of the materials, leading to changes in the XRD diffraction patterns.Before sintering, the XRD diffraction pattern of a material typically shows distinct peaks corresponding to the crystal planes of the different phases present in the sample. These peaks are a fingerprint of the crystallographic structure and can provide valuable information about the phase composition and crystallinity of the material. After sintering, the XRD diffraction pattern may change significantly due to the rearrangement of atoms and the formation of new crystallographic phases.This can result in shifts in the peak positions, changes in peak intensities, and the appearance of new peaks in the XRD pattern.The changes in the XRD diffraction pattern before and after sintering can provide important insights into the sintering process and the resulting microstructure of the material. For example, the disappearance of certain peaksin the XRD pattern after sintering may indicate the dissolution of certain phases or the formation of solid solutions. On the other hand, the appearance of new peaks may suggest the formation of new crystallographic phases or the recrystallization of the material. These changes in the XRD pattern can be used to optimize the sintering process and tailor the properties of the material for specific applications.In addition to providing information about the phase composition and microstructure of the material, the XRD diffraction pattern before and after sintering can also be used to monitor the degree of densification and the grain growth during the sintering process. The peak broadeningand shifting in the XRD pattern can provide quantitative information about the grain size and the degree of crystallinity of the material. This can be valuable for controlling the sintering parameters and optimizing the mechanical and electrical properties of the material.Furthermore, the changes in the XRD diffraction pattern before and after sintering can also be used to study the thermal stability and the phase transformations of the material. By analyzing the evolution of the XRD pattern as a function of temperature, it is possible to identify the temperature at which certain phase transitions occur and to study the kinetics of these transformations. This can be crucial for understanding the thermal behavior of the material and for designing sintering processes that minimize the formation of undesirable phases.In conclusion, the XRD diffraction pattern before and after sintering provides valuable information about the phase composition, microstructure, densification, grain growth, and thermal stability of the material. By analyzing the changes in the XRD pattern, it is possible to optimizethe sintering process and tailor the properties of the material for specific applications. This makes XRD an indispensable tool for studying the effects of sintering on the crystallographic structure of materials.。

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