清华材料科学基础课件(英文)skia_02
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材料化学全英文课件PPT课件
h
12
c
(1 1 0)
a
[100 ]
[110 ]
(100)
Planes and their negatives are identical. Therefore, (02)0(020).
In some situation, p identical.
In cubic systems, a direction that has the same indices as a plane is perpendicular to that plane.
h
2
2.5.2 Plane indices
1. Steps to determinate the plane indices: Establish a set of coordinate axes. Find the intercepts of the planes to be indexed on a, b and c axes (x, y, z).
Lesson five
h
1
2.5 Indices of Crystal Planes and Directions
2.5.1 What’s crystal planes and directions?
The atomic planes and directions passing through the crystal are called Crystal Planes and Crystal Directions respectively.
h
9
2. The important direction in cubic crystals: <100> : crystal axes <110> : face diagonal <111> : body diagonal <112> : apices to opposite face-centers
2材料科学基础英文版课件_(13)
– Time-dependent process, the rate of mass transfer is expressed as a diffusion flux (J)
JM At
Mass transferred through a crosssectional area
Diffusion time
Mathematics of Diffusion (5)
The diffusion equation is represented by
C (DC)
t
x
x
Fick’s second law C is a function of x and t
If D is independent of the composition, the above equation changes to
J
Mathematics of Diffusion (3)
For steady-state diffusion, the diffusion flux is proportional to the concentration gradient
The mathematics of steady-state diffusion in one dimension is given by
For t>0, Cx=Cs at x=0 Cx=Co at x=
Area across which the diffusion occurs
In differential form
J 1 dM A dt
J = Mass transferred through a unit area per unit time (g/m2 s))
JM At
Mass transferred through a crosssectional area
Diffusion time
Mathematics of Diffusion (5)
The diffusion equation is represented by
C (DC)
t
x
x
Fick’s second law C is a function of x and t
If D is independent of the composition, the above equation changes to
J
Mathematics of Diffusion (3)
For steady-state diffusion, the diffusion flux is proportional to the concentration gradient
The mathematics of steady-state diffusion in one dimension is given by
For t>0, Cx=Cs at x=0 Cx=Co at x=
Area across which the diffusion occurs
In differential form
J 1 dM A dt
J = Mass transferred through a unit area per unit time (g/m2 s))
清华材料科学基础课件skja_24
{111} ==> collapse to form disk of point defects ==> dislocation loop
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Examples and Discussions
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Exercise
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Thank you !
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§5.17 Frank Partial Dislocation in FCC
1. Frank Partial is formed by extracting or inserting part of {111} plane.
n egative Frank b1 3111
[001 ]
未滑 A
C
B
[001 ]
已滑
AB
CA
BC
A
A
C
C
1 [ 1 12 ]
2
[ 1 10 ]
FCC {111}<112> BCC {112}<111> HCP {1012}1011
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Characteristic of Shockley Partial:
1. It is the boundary between faulted and unfaulted.
2. It can be edge, screw or mixed zones dislocation.
3. Even in edge orientation, it can not climb.
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Examples and Discussions
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Exercise
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Thank you !
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§5.17 Frank Partial Dislocation in FCC
1. Frank Partial is formed by extracting or inserting part of {111} plane.
n egative Frank b1 3111
[001 ]
未滑 A
C
B
[001 ]
已滑
AB
CA
BC
A
A
C
C
1 [ 1 12 ]
2
[ 1 10 ]
FCC {111}<112> BCC {112}<111> HCP {1012}1011
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Characteristic of Shockley Partial:
1. It is the boundary between faulted and unfaulted.
2. It can be edge, screw or mixed zones dislocation.
3. Even in edge orientation, it can not climb.
skja_10
Wurtzite: (Zn Cd Mn)S (Cd Mn)Se
精品课件
3. NiAs structure Example: (Cr Fe Co Ni)(S Se Sb) (Fe Co)Te (Mn Fe Ni Pt Cn)Sn Ni(As Sb Bi)
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Structure
• Normal state —— Ni : As = 1 : 1
⑷ Metallic character
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§3.9 Size Factor Compounds
Ⅰ. Interstitial phases (Interstitial compounds)
Condition A >> B
B: H (0.46), B (0.97), C (0.77), N (0.71)
⑴ Some metallic properties ⑵ Hard and brittle ⑶ For size factor compounds
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Ⅱ. Three principles for the structure
1. space-filling principle: Atoms tend to fill the space as
For Alloys of IB or transition metals, and B group metals phases with sane or similar structure occur at approximately some electron concentration(e/a) these alloys are therefore called as electron compounds
For example:
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3. NiAs structure Example: (Cr Fe Co Ni)(S Se Sb) (Fe Co)Te (Mn Fe Ni Pt Cn)Sn Ni(As Sb Bi)
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Structure
• Normal state —— Ni : As = 1 : 1
⑷ Metallic character
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§3.9 Size Factor Compounds
Ⅰ. Interstitial phases (Interstitial compounds)
Condition A >> B
B: H (0.46), B (0.97), C (0.77), N (0.71)
⑴ Some metallic properties ⑵ Hard and brittle ⑶ For size factor compounds
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Ⅱ. Three principles for the structure
1. space-filling principle: Atoms tend to fill the space as
For Alloys of IB or transition metals, and B group metals phases with sane or similar structure occur at approximately some electron concentration(e/a) these alloys are therefore called as electron compounds
For example:
skja_03 Fundamentals of Crystallography 材料科学基础(英文课件)
2020/7/3
Seven Crystal Systems
Triclinic
Monoclinic
Orthorhombic Tetragonal Cubic Hexagonal Rhombohedral
a≠b≠c ，α≠β≠γ≠90° a≠b≠c ， α＝β＝90°≠γ
α＝γ＝90°≠β a≠b≠c ，α＝β＝γ＝90° a＝b≠c ，α＝β＝γ＝90° a＝b＝c ，α＝β＝γ＝90° a＝b≠c ，α＝β＝90°γ＝120°
5. Draw a primitive cell for BCC lattice.
Thank you !
3
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We identify 14 types of unit cells, or Bravais lattices, grouped in seven crystal systems.
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Ⅰ.Seven crystal systems
All possible structure reduce to a small number of basic unit cell geometries. ① There are only seven, unique unit cell shapes that can be stacked together to fill three-dimensional. ② We must consider how atoms can be stacked together within a given unit cell.
120o
120o 120o
c
a ba
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Examples and Discussions
Seven Crystal Systems
Triclinic
Monoclinic
Orthorhombic Tetragonal Cubic Hexagonal Rhombohedral
a≠b≠c ，α≠β≠γ≠90° a≠b≠c ， α＝β＝90°≠γ
α＝γ＝90°≠β a≠b≠c ，α＝β＝γ＝90° a＝b≠c ，α＝β＝γ＝90° a＝b＝c ，α＝β＝γ＝90° a＝b≠c ，α＝β＝90°γ＝120°
5. Draw a primitive cell for BCC lattice.
Thank you !
3
2020/7/3
We identify 14 types of unit cells, or Bravais lattices, grouped in seven crystal systems.
2020/7/3
Ⅰ.Seven crystal systems
All possible structure reduce to a small number of basic unit cell geometries. ① There are only seven, unique unit cell shapes that can be stacked together to fill three-dimensional. ② We must consider how atoms can be stacked together within a given unit cell.
120o
120o 120o
c
a ba
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Examples and Discussions
材料科学基础双语课件
control the material properties (for example by altering the
grain structure, or the presence of defects in the atom
packing) or to fabricate the material into the desired shape.
extra material, joining parts (e.g., by soldering or welding),
forming (forging, rolling, bending, etc.), or compacting particles which are then fused together (sintering, used for
gases (and most engineering materials are used in solid
form).
1.1 What is Materials Science and Engineering?
It may seem abstract and remote from real engineering to
The Science and Engineering of Materials
Aim
English atmosphere: speaking, reading, writing and lisห้องสมุดไป่ตู้ening; Specialty vocabulary; Specialty knowledge;
form. As this mixture solidifies, different structures form as a function of temperature. The phase diagrams that provide
grain structure, or the presence of defects in the atom
packing) or to fabricate the material into the desired shape.
extra material, joining parts (e.g., by soldering or welding),
forming (forging, rolling, bending, etc.), or compacting particles which are then fused together (sintering, used for
gases (and most engineering materials are used in solid
form).
1.1 What is Materials Science and Engineering?
It may seem abstract and remote from real engineering to
The Science and Engineering of Materials
Aim
English atmosphere: speaking, reading, writing and lisห้องสมุดไป่ตู้ening; Specialty vocabulary; Specialty knowledge;
form. As this mixture solidifies, different structures form as a function of temperature. The phase diagrams that provide
2材料科学基础英文版课件_(12)
• Deformation-induced nonequilibrium vacancies
Point Defects – Point Defects in Metals (4)
The molar free energy of the crystal containing Xv mole of vacancies:
பைடு நூலகம்• There is always some level of impurity or foreign atoms in a metal, leading to the formation of an alloy
• Alloys – solid solutions and intermetallics • Concept: solvent – the matrix or host; solute
• Thermal equilibrium vacancies and interstitials
• Quenching-induced nonequilibrium vacancies and interstitials
• Irradiation-induced nonequilibrium vacancies and interrstitials
Point Defects – Point Defects in Metals (1)
1. Vacancies and Interstitials (self-interstitials)
Frenkel pair: vacancy + interstitial
Schottky defect: moving an atom to the surface produces a vacancy
Point Defects – Point Defects in Metals (4)
The molar free energy of the crystal containing Xv mole of vacancies:
பைடு நூலகம்• There is always some level of impurity or foreign atoms in a metal, leading to the formation of an alloy
• Alloys – solid solutions and intermetallics • Concept: solvent – the matrix or host; solute
• Thermal equilibrium vacancies and interstitials
• Quenching-induced nonequilibrium vacancies and interstitials
• Irradiation-induced nonequilibrium vacancies and interrstitials
Point Defects – Point Defects in Metals (1)
1. Vacancies and Interstitials (self-interstitials)
Frenkel pair: vacancy + interstitial
Schottky defect: moving an atom to the surface produces a vacancy
材料科学基础英文版课件（ＰＤＦ）
Law • Steady State: the concentration profile doesn't
change with time.
Steady State:
J x(left)
J x(right) J x(left) = J x(right)
x
Concentration, C, in the box doesn’t change w/time.
Non Steady State Diffusion
• Concentration profile,
dx
C(x), changes with time. J (left)
J (right)
• To conserve matter:
J (right)
− J (left)
=
dC −
dx
dt
dJ = − dC
ΔJ y
=
− ∂J y ∂y
dxdydzδt
ΔJ z
= − ∂J z ∂z
dxdydzδt
对整个元体积：
−
⎜⎜⎝⎛
∂J x ∂x
+
∂J y ∂y
+
∂J z ∂z
⎟⎟⎠⎞dxdydzδt
若 δt 时间内粒子浓度变化δc ，则在dxdydz
元体积中粒子变化为
δcdxdydz
∴ ∂c ∂t
=
−⎜⎜⎝⎛
∂J x ∂x
Fick’s Second Law
δt 时间内沿x方向扩散
元体积dxdydz
流入的粒子数： J x dydzδt
流出的粒子数：
(J x
+
∂J x ∂x
dx)dydzδt
材料科学基础ppt课件
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• 这类聚合物是由缩聚反应或开环聚合而成的， 因主链带极性，易水解，醇解或酸解
• 优点：耐热性好，强度高 • 缺点：易水解
• 这类聚合物主要用作工程塑料
12
元素高分子
➢主链中不含碳原子，而是由Si 、B 、As等元素和O元 素组成，但在侧链上含有有机取代基团。这类高分 子兼具无机和有机高分子特性，如有机硅高分子。
• 支化高分子的形式：星形(Star)、 梳形 (Comb)、无规(Random)
23
网状(交联)大分子
• 缩聚反应中有三个或三个以上官能 度的单体存在时，高分子链之间通 过支链联结成一个三维空间网形大 分子时即成交联结构
• 交联与支化有本质区别 支化(可溶，可熔，有软化点) 交联(不溶，不熔，可膨胀)
2
•
3-1 材料组成和结构的基本内容
Principal Contents of Materials Composition and Structures
• 材料的组成： 构成材料的基本单元的成分及数目
• 材料的结构： 材料的组成单元(即原子或分子)之间相互吸引 和相互排斥作用达到平衡时在空间的几何排列。
(2)
结构单元 的键接方式 ( 几何构型 Geometric
Configuration) (链节)
16
加聚
缩聚
• 由以上知：
• 由于高分子是链状结构，所以把简单重复(结构)单元称为“链节”(chains) • 简单重复(结构)单元的个数称为聚合度DP(Degree of Polymerization1
28
无 规 共 聚 ( random)
• 两种高分子无规则地平行联结
ABAABABBAAABABBAAA
• 这类聚合物是由缩聚反应或开环聚合而成的， 因主链带极性，易水解，醇解或酸解
• 优点：耐热性好，强度高 • 缺点：易水解
• 这类聚合物主要用作工程塑料
12
元素高分子
➢主链中不含碳原子，而是由Si 、B 、As等元素和O元 素组成，但在侧链上含有有机取代基团。这类高分 子兼具无机和有机高分子特性，如有机硅高分子。
• 支化高分子的形式：星形(Star)、 梳形 (Comb)、无规(Random)
23
网状(交联)大分子
• 缩聚反应中有三个或三个以上官能 度的单体存在时，高分子链之间通 过支链联结成一个三维空间网形大 分子时即成交联结构
• 交联与支化有本质区别 支化(可溶，可熔，有软化点) 交联(不溶，不熔，可膨胀)
2
•
3-1 材料组成和结构的基本内容
Principal Contents of Materials Composition and Structures
• 材料的组成： 构成材料的基本单元的成分及数目
• 材料的结构： 材料的组成单元(即原子或分子)之间相互吸引 和相互排斥作用达到平衡时在空间的几何排列。
(2)
结构单元 的键接方式 ( 几何构型 Geometric
Configuration) (链节)
16
加聚
缩聚
• 由以上知：
• 由于高分子是链状结构，所以把简单重复(结构)单元称为“链节”(chains) • 简单重复(结构)单元的个数称为聚合度DP(Degree of Polymerization1
28
无 规 共 聚 ( random)
• 两种高分子无规则地平行联结
ABAABABBAAABABBAAA
2材料科学基础英文版课件_(10)
Tilt boundary
Twist boundary
Use to represent the extent of CSL e.g., 3, 15, etc.
CSL boundary (coincidence site lattice boundary) Special boundary
Grain boundary segregation
External Surfaces
• Surface atoms are not bonded to the nearest neighbors above the surface, leading to a higher energy state, i.e., a surface energy
• To be stable, materials need to reduce the surface energy.
• Observation of dislocations
Dark lines - dislocations
Plane Defects
Features: two dimensional
Outline
• External surfaces • Grain boundaries • Twin boundaries • Stacking faults • Phase boundaries
• To reduce the surface energy, the materials tend to minimize the total surface area
Grain Boundaries
In polycrystalline materials, a grain boundary is the boundary between two adjacent grains which have different orientations
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Solution
Z1Z 2e 2 Fattractive 40 a 2
Z1Z 2e 2 (2)( 2)(1.60 10 19 C) 2 a0 40 Fattractive 4 [8.85 10 12 C 2 ( N m 2） ](1.49 10 8 N) 0.249 nm
Neutral atom
E
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材料科学基础
Van Der waals bonding
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材料科学基础
A dipole moment is defined as the charge value multiplied by the separation distance between positive and negative charges, or
材料科学基础
Fundamental of Materials
Lesson two
2019/3/12 材料科学基础
§1.2 Atomic bonding
Ⅰ.Bonding forces and energies
FN FA FR
FN : net force FA : attractive force
FR : repulsive force
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材料科学基础
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材料科学基础
Bonding enertems:
E N E A ER
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材料科学基础
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材料科学基础
Ⅱ.Primary interatomic bonds
qd
dipole moment
q magnitude of electric charge d separation distance between the charge centers
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材料科学基础
1. Van der waals interactions London forces If the interactions are between two dipoles that are induced in atoms or molecules, we refer to them as London forces.
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材料科学基础
3. Metallic bonding Metallic bonding occurs in solid metals. In metals in solid state, atoms are packed relatively close together in a systematic pattern or crystal structure.
Ionic bonding is always found in compounds that are composed of both metallic and nonmetallic elements, elements that are situated at the horizontal extremities of the periodic table.
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材料科学基础
Ⅲ.Secondary bonding （Van Der waals bonding)
The driving force for secondary bonding is the attraction of the electric dipoles contained in atoms or molecules. An electric dipole moment is created when two equal and opposite charges are separated.
材料科学基础
Interionic Energies
Z1Z 2e 2 b Enet n 40 a a
Attractive energy Repulsive energy
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材料科学基础
Example problem 2.1
If the attractive force between a pair of Mg2+and S2- is 1.49×10-8N and if the S2- ion has a radius of 0.184nm, calculate a value for the ionic radius of the Mg2+ ion in nanometers.
Z1, Z2＝number of electrons removed or added from the atoms during the ion formation
e ＝electron charge
a ＝interionic separation distance
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ε0＝permittivity of free space＝8.85×10-12C2/(N· m2)
1. Ionic bonding
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材料科学基础
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材料科学基础
Interionic Forces
Z1Z 2e 2 Fattractive 40 a 2
nb Frepulsive n1 a
Z1Z 2e 2 nb Fnet n1 2 40 a a
又a0 rMg2 rS 2 rMg2 a0 rS 2 0.249nm 0.184nm 0.065nm
2019/3/12 材料科学基础
2. Covalent bonding
Materials with covalent bonding are characterized by bonds that are formed by sharing of valence electrons among two or more atoms.