Growth of Casting Microcrack and Micropore in Single-crystal Superalloys Analysed by Three-Dimen
高锰钢铸件裂纹产生的原因及预防措施
收稿日期 :Байду номын сангаас2005 10 28; 作者简介 : 张军强 ( 1969 修订日期 : 2006 02 07 ) , 陕西渭南人 , 工程师 . 从事生产管理工作 .
因裂纹造成非正常失效, 导致产品寿命降低。因此研 究高锰钢铸件裂纹产生的原因, 从而采取有效的预防 措施, 便成为铸造工作者的重要课题。本文根据生产 实践经验 , 试图阐明高锰钢铸件产生裂纹的机理, 从而 找到有效的预防措施 , 以求推动该课题的发展。 1 高锰钢铸件裂纹产生的原因分析 1. 1 在铸造生产过程中高锰钢铸件裂纹产生的原因 分析 高锰钢铸件产生裂纹的内在 原因主要有 3 个方 面: 高锰钢线收缩值高达 2. 4% ~ 3. 0% 是碳钢线收 缩值的 2 倍, 因此当高锰钢铸件在凝固收缩过程中收
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铸造技术 F OU N DRY T ECH NO LO GY
V ol. 27 N o. 4 A pr. 2006
高锰钢铸件裂纹产生的原因及预防措施
张军强 , 张文斌 , 王红旗
农科股份有限公司, 陕西 渭南 714100)
摘要 : 根据高锰钢生产的实践经验 , 提出了高锰钢铸 件在铸造生产过程中裂纹产生的 机理及受大 冲击载荷 高锰钢铸件 在使用 过程中裂纹产生发展的机理 。 认为铸件在使用过程中 的非正 常失效 的原因 主要是 由于铸件 内部存 在着显 微裂纹 、 碳化 物孔 洞、 晶界上的磷共晶 、 非金属夹杂物 、 缩孔 、 缩松等缺陷造成 。 从铸件的 结构设计 、 化学成分的选取 、 冶炼 、 浇注 、 造型 、 清理及热 处理各个环节中根据高锰钢的特点 , 制订出合理的工 艺并严 格执行 而获得优 质的铸 件 。 通过 采取细化 晶粒 、 强化 脱氧 、 脱磷 来预防铸件产生裂纹 。 生产实践证明 : 以上措施是消除或减小高锰钢铸件裂纹的有效手段 。 关键词 : 高锰钢 ; 裂纹 ; 预防措施
助溶剂法生长碳化硅晶体
助溶剂法生长碳化硅晶体英文回答：Growing silicon carbide crystals using the solvent-assisted method is a common technique in crystal growth research. This method involves the use of a solvent to enhance the solubility of the silicon and carbon precursors, allowing for the controlled growth of high-quality crystals.In this process, a solvent is chosen that has a high solubility for both the silicon and carbon precursors. Common solvents used include toluene, xylene, and acetone. The solvent is then mixed with the precursors, such as silicon tetrachloride (SiCl4) and a carbon source like propane or acetylene.The solvent-assisted method offers several advantages over other crystal growth techniques. Firstly, it allowsfor better control over the crystal growth process,resulting in higher quality crystals with fewer defects.The solvent acts as a buffer, preventing the formation of impurities and ensuring the crystal grows in a controlled manner.Additionally, the solvent-assisted method enables the growth of larger crystals compared to other methods. The enhanced solubility provided by the solvent allows for the incorporation of more silicon and carbon atoms into the crystal lattice, leading to larger crystal sizes.To illustrate this, let's consider an analogy. Imagine you are baking a cake. The solvent in this case is like the cake batter, which helps to dissolve and evenly distribute the ingredients (silicon and carbon precursors) throughout the mixture. Without the batter, the ingredients may clump together or not mix properly, resulting in an uneven and poorly formed cake (crystal).Now, let's move on to the 中文回答：助溶剂法生长碳化硅晶体是晶体生长研究中常用的技术。
我国的微雕技术作文
我国的微雕技术作文英文回答：Micro-carving technology in China has a long history and has been widely used in various fields. Micro-carving, also known as micro-sculpture, is a traditional Chinese art form that involves carving intricate designs or sculptures on a very small scale. This delicate and intricate art form requires a high level of skill and precision, and it has been passed down through generations of artisans.The micro-carving technique in China is often used in the creation of jewelry, decorative art pieces, and even in the restoration of cultural relics. The level of detail and precision that can be achieved through micro-carving is truly remarkable, and it has become a highly valued and respected art form in China.One of the most famous examples of micro-carving in China is the micro-carving on the surface of a single grainof rice. This incredible feat of artistry and skill has gained international recognition and has become a symbol of the level of craftsmanship that can be achieved through micro-carving.The tools used in micro-carving are extremely small and delicate, and the process requires a steady hand and a great deal of patience. Artisans often use specialized magnifying tools to ensure that they can achieve the level of detail and precision required for micro-carving.In recent years, micro-carving has also gained popularity as a form of modern art in China. Contemporary artists are using micro-carving techniques to create innovative and unique works of art that push the boundaries of traditional micro-carving.Overall, the micro-carving technique in China is a testament to the skill and artistry of Chinese artisans. It is a highly respected and valued art form that continues to evolve and inspire new generations of artists.中文回答：中国的微雕技术源远流长，已经被广泛运用于各个领域。
介绍微雕技艺作文英语
介绍微雕技艺作文英语Title: The Art of Microcarving: A Delicate Craft。
Microcarving, a delicate art form originating from ancient cultures, has evolved into a sophisticated technique known as micro-engraving or micro-sculpting. This intricate artistry involves carving minuscule designs onto surfaces, often requiring specialized tools and a meticulous hand. In this essay, we delve into the realm of microcarving, exploring its history, techniques, and contemporary applications.Historical Roots:Microcarving finds its roots in ancient civilizations such as Egypt, Greece, and China. These cultures employed microcarving techniques to adorn jewelry, pottery, and architectural elements with intricate designs. In ancient China, artisans mastered the art of microcarving on materials like jade and ivory, creating exquisitesculptures and ornaments that are revered to this day.Techniques:Modern microcarving techniques have advanced significantly, owing to technological innovations and refined craftsmanship. Artisans utilize specialized tools such as microscopes, engraving needles, and lasers to achieve precision in their work. The process begins with selecting a suitable material, often gemstones like diamonds or rubies due to their hardness and clarity. The artisan then meticulously sketches the design before delicately carving it onto the surface of the material. The intricacy of microcarving requires immense patience and skill, as even the slightest error can ruin the entire piece.Challenges and Rewards:Microcarving presents a unique set of challenges compared to traditional carving methods. Working on such a small scale demands steady hands, acute vision, and anunderstanding of the material's properties. Moreover, the fragility of the medium means that one must exercise caution throughout the entire process to avoid accidental damage. However, the rewards of mastering microcarving are unparalleled. The ability to breathe life into minute details and create awe-inspiring pieces of art is immensely gratifying for artisans and viewers alike.Contemporary Applications:In the modern era, microcarving has found diverse applications across various industries. In the realm of jewelry, micro-engraving allows designers to adorn pieces with intricate motifs, adding a touch of elegance and sophistication. Beyond adornment, microcarving has also found utility in security features for banknotes and identification documents. Microscopically engraved patterns and images serve as anti-counterfeiting measures, enhancing the security and authenticity of valuable documents.Conclusion:In conclusion, microcarving stands as a testament to the ingenuity and skill of artisans throughout history. From its humble beginnings in ancient civilizations to its contemporary applications in technology and art, microcarving continues to captivate and inspire. As technology advances and artistic boundaries expand, the art of microcarving will undoubtedly evolve, pushing the limits of what is possible on a minuscule scale.。
难熔金属粉末冶金制备新技术
难熔金属的粉末冶金制备新技术何勇学号：153312086粉末冶金研究院摘要：本文简要介绍了几种难熔金属的制备新技术，包括三种现代粉末冶金烧结技术（微波烧结、放电等离子烧结、选择性激光烧结）与两种近静成型技术（3D打印、金属粉末注射成形）。
介绍其制备方法的基本原理、技术优势以及应用现状，并在最后简单阐述材料制备技术的发展趋势。
先进烧结技术具有烧结温度低、烧结速度快、晶粒组织细化、结构均匀可控等优点，同时节约能源，生产效率高，是未来难熔金属制品致密化过程的优良选择；近静成型技术摒弃了传统材料制品制备和加工分开进行的传统工艺，大大缩短了生产周期，已成为当今难熔金属材料研究的热点，在高新尖端领域拥有十分可观的前景。
关键词：难熔金属；制备工艺技术；粉末冶金Abstract: This paper briefly introduces several new techniques of preparation of refractory metal, including three modern sintering technologies such as microwave sintering and two kinds of near net shape techniques. The basic principles，advantages and research status of these methods are claimed in the main paragraph. At the last part, some development trend of refractory metal materials are listed briefly.Not only do they possess unique advantages on rapid heating rate, short sintering time, inhibiting grain growth and controlling microstructure, but also show enormous industrial application value and prospect in terms of short production cycle and high efficiency energy saving, so the new sintering techniques have become a present research focus in material field.Near net shape technology has a very considerable prospects in the high-tech frontier because it greatly shortens the production cycle.Key words: refractory metal; preparation technique; powder metallurgy1 前言难熔金属[1]一般是指熔点在2000℃以上的过渡金属元素，广义上包括钨（W）、钼（Mo）、钽（Ta）、铌（Nb）、钛（Ti）、钒（V）、铬（Cr）、锆（Zr）等十几种元素。
模仿核州记写一篇微雕作文
模仿核州记写一篇微雕作文英文回答：A Microscopic Masterpiece: The Intricate Art of Microtechnology.Microtechnology, the art of creating intricate structures on a minuscule scale, is a testament to human ingenuity and the advancement of science. This cutting-edge technology has opened up countless possibilities in diverse fields, from medicine and biotechnology to microelectronics and manufacturing.The humble origins of microtechnology can be traced back to the early 20th century. It was not until the invention of the scanning tunneling microscope in 1981, however, that scientists gained the ability to manipulate and visualize matter at the atomic level. This breakthrough paved the way for the development of advanced lithography techniques, enabling the precise fabrication of microscopicstructures.Today, microtechnology encompasses a wide range of processes, including photolithography, electron beam lithography, and focused ion beam milling. These techniques allow engineers to create structures with feature sizes ranging from nanometers to micrometers. The applications of microtechnology are vast and ever-expanding.In the medical realm, microtechnology hasrevolutionized diagnostics and treatment. Microneedles, for example, provide a minimally invasive method for drug delivery and blood testing. Microfluidic devices enable precise control of fluids, making them ideal for DNA sequencing and cell analysis. Microrobots, controlled by external magnetic fields or light, offer promising avenues for targeted drug delivery and minimally invasive surgery.Microtechnology is also transforming the field of microelectronics. Microchips, essential for countless electronic devices, are becoming increasingly smaller and more powerful thanks to microtechnology. Microwires andmicrobatteries enable new possibilities for flexible electronics and wearable devices.In the manufacturing sector, microtechnology is enabling the creation of high-precision components and devices. Micromachined sensors, for instance, improve performance and reliability in aerospace and automotive applications. Micromolds and microfabrication techniques facilitate the mass production of micro-optical components, revolutionizing the telecommunications industry.The possibilities offered by microtechnology are limitless. As scientists continue to push the boundaries of this technology, we can expect even more transformative applications in healthcare, electronics, manufacturing, and other industries.中文回答：微观杰作，微加工技术的精妙艺术。
描写微雕技术的作文600字
描写微雕技术的作文600字英文回答：Micro-carving, known as microengraving or micro-etching, is an art form that involves engraving intricate designs or images onto extremely small surfaces, typically using specialized tools such as magnifying glasses, scalpels, and lasers. The resulting works of micro-carving are often breathtakingly detailed and intricate, showcasing the skill and precision of the artist.The history of micro-carving can be traced back to ancient times, with early examples found in prehistoriccave paintings and artifacts. However, it was during the Renaissance period in Europe that micro-carving truly flourished, as skilled artisans used magnifying glasses to create intricate engravings on jewelry, watches, and other small objects.Today, micro-carving continues to captivate artists andcollectors alike, with contemporary practitioners pushing the boundaries of the art form through innovative techniques and materials. Modern micro-carving often utilizes advanced technologies such as laser engraving and nano-machining, allowing artists to create designs with unprecedented detail and precision.Micro-carving has found applications in a wide range of fields, including art, jewelry making, watchmaking, and medical technology. In art, micro-carved sculptures and engravings are highly prized for their intricate beauty and craftsmanship. In jewelry making, micro-carving is used to create intricate designs and textures on rings, pendants, and other pieces. In watchmaking, micro-carving is employed to engrave intricate patterns on watch faces and movements. In medical technology, micro-carving techniques are used to create precision components for surgical instruments and implants.中文回答：微雕，又称微刻或微蚀刻，是一种在极小的表面上雕刻精细图案或图像的艺术形式，通常使用放大镜、手术刀和激光等专门工具。
PMMA微流控芯片注射成型多目标优化实验研究
第 54 卷第 7 期2023 年 7 月中南大学学报(自然科学版)Journal of Central South University (Science and Technology)V ol.54 No.7Jul. 2023PMMA 微流控芯片注射成型多目标优化实验研究吴旺青，雷益华，单志颖，蒋炳炎(中南大学 机电工程学院，极端服役性能精准制造全国重点实验室，湖南 长沙，410083)摘要：随着微流控技术的不断发展和聚合物材料的广泛应用，注射成型技术因其快速、低成本、大批量的生产等优势而成为聚合物微流控芯片成型制造的主要方式之一，但也存在微结构成型难、残余应力与宏观变形等问题。
为表征聚合物微流控芯片成型能力、研究工艺参数对成型质量的影响，采用正交实验研究熔体温度、注射压力、注射速度、保压压力和保压时间对聚甲基丙烯酸酯(PMMA)微流控芯片微通道复制度、残余应力、宏观翘曲变形三种指标的影响规律，并利用灰色关联分析法对三种指标进行多目标优化得到最优工艺参数。
研究结果表明：影响微通道复制度最主要的因素是注射速度和熔体温度，影响残余应力与翘曲变形最主要的因素是熔体温度；利用正交实验对三种指标优化得到的最优参数存在差异，而利用灰色关联分析方法进行多目标优化得到了微通道复制度高、残余应力小和翘曲变形小的高质量芯片。
最优注射成型工艺参数如下：熔体温度为245 ℃、注射压力为160 MPa 、注射速度为50 cm 3/s 、保压压力为70 MPa 和保压时间为5 s 。
关键词：微流控芯片；注射成型；多目标优化中图分类号：TQ320.66 文献标志码：A 文章编号：1672-7207（2023）07-2630-12Experimental study on multi-objective optimization of PMMAmicrofluidic chip injection moldingWU Wangqing, LEI Yihua, SHAN Zhiying, JIANG Bingyan(State Key Laboratory of Precision Manufacturing for Extreme Service Performance, School of Mechanical andElectrical Engineering, Central South University, Changsha 410083, China)Abstract: With the continuous development of microfluidic technology and the wide application of polymer materials, injection molding technology has become one of the main ways of polymer microfluidic chip molding and manufacturing because of its advantages of fast speed, low cost and mass production. However, there are also some problems such as difficulty in forming microstructure, residual stress and macroscopic deformation. In order to characterize the molding ability of polymer microfluidic chip and study the influence of process parameters on收稿日期： 2022 −09 −02； 修回日期： 2022 −11 −18基金项目(Foundation item)：国家自然科学基金重点国际(地区)合作研究项目(51920105008) (Project(51920105008) supported bythe National Natural Science Foundation of China for Key International(Regional) Joint Research Program)通信作者：吴旺青，博士，教授，从事高聚物微纳成型加工理论与应用研究；E-mail ：**************.cnDOI: 10.11817/j.issn.1672-7207.2023.07.010引用格式： 吴旺青, 雷益华, 单志颖, 等. PMMA 微流控芯片注射成型多目标优化实验研究[J]. 中南大学学报(自然科学版), 2023, 54(7): 2630−2641.Citation: WU Wangqing, LEI Yihua, SHAN Zhiying, et al. Experimental study on multi-objective optimization of PMMA microfluidic chip injection molding[J]. Journal of Central South University(Science and Technology), 2023, 54(7): 2630−2641.第 7 期吴旺青，等：PMMA微流控芯片注射成型多目标优化实验研究molding quality, the influence of melt temperature, injection pressure, injection speed, holding pressure and holding time on microchannel complex system, residual stress and macroscopic warp deformation of polymethacrylate(PMMA) microfluidic chip was studied by orthogonal experiment. The optimal parameters were obtained by multi-objective optimization of the three indexes using grey correlation analysis method. The results show that the injection speed and melt temperature are the most important factors affecting the microchannel replication, and the melt temperature is the most important factor affecting the residual stress and warpage deformation. The optimum parameters of the three indexes are different from each other by orthogonal experiment, and the high quality chip with high complex microchannel system, low residual stress and small warpage deformation is obtained by multi-objective optimization using grey correlation analysis method. The optimal parameters are as follows. The melt temperature is 245 ℃, the injection pressure is 160 MPa, the injection speed is50 cm3/s, the pressure holding pressure is 70 MPa and the pressure holding time is 5 s.Key words: microfluidic chip; injection molding; multi-objective optimization随着科技的进步，实验室检测技术的要求也越来越高，尤其是在化学分析、医学检验、生命科学等领域[1−2]。