材料科学基础英文版课件
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材料科学基础英文版课件()
Principles of Fracture Mechanics (1)
Brittle fracture of normally ductile materials requires us to have a good understanding of the mechanisms of fracture. To do this, we need to know the knowledge of fracture mechanics Concerned with the relationship between material properties, stress level, crackproducing flaws, and crack propagation mechanisms
Ductile Fracture (1)
Features of ductile fracture
Moderately ductile Some deformation
Macroscopically
Highly ductile Considerable deformation
Necking down to Some necking a point
Kt
m o
2( a )1 2
t
Principles of Fracture Mechanics (3)
It is seen from the above that stress concentration occurs
Not only at microscopic flaws or cracks
Brittle Fracture (2)
Fracture surface markings for brittle fracture
材料科学基础英文版课件_(12)
= ~3.810-4
For most metals, the value near the melting point is in the range of 10-3 to 10-4
Chapter 5
Imperfections in Solids
Lecturer: Shenhua SONG
Outline
• Point defects • Linear defects • Plane defects
1. Point defects in metals 2. Point defects in ceramics
Formation – leading to an increase of internal energy – free energy increase (G = H - TS, H=U+PV, U - H - G ) Formation – leading to an increase of entropy (randomness) –free energy decrease At a given temperature, there must be a concentration of point defects at which the free energy of the system has a minimum value.
equilibrium for a certain amount of material and N is the total number of atomic sites
Point Defects – Point Defects in Metals (6)
~3 for most metals e.g. iron (Fe): Hv is ~1.4 eV per atom, the melting points is 1808K (1535oC), the equilibrium vacancy concentration is
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-(13)
Ductility
The ability of a material to be stretched without breaking.
Toughness
The ability of a material to absorb energy before fracturing.
Physical Properties
Some common examples of polymers include plastic, rubber, and fiberglass.
Polymers can be natural or synthetic.
Composites
Composites are materials that consist of two or more materials with different physical and chemical properties.
Nondestructive testing techniques: 超声波检测，射线检测，涡流检测等 。
02
Materials Properties
Mechanical Properties
Elasticity
The ability of a material to return to its original shape after being deformed by an external force.
Metals
Metals are materials that are typically ductile, malleable, and conduct electricity well.
They are often used in the manufacturing of various
材料科学基础英文版课件_(11)
d
e
g
f
7c/8
(2/3,1/3,3/4)
dae a
Ro = a2/2 – R
= 2R – R =
g
f
0.414R (a=2R)
(2/3,1/3,7/8)
Rt = (3/8)c – R = (3/8)x1.633a –R = 0.225R (a=2R)
Metallic crystal structures (11)
Metallic crystal structures (7)
3) Hexagonal close-packed (HCP) crystal structure
Each unit cell contains 6 atoms (12(1/6) + 2(1/2) + 3 = 6)
2R = a R = a/2
Two other features: coordination number (CN) and atomic packing factor (APF) CN: the number of nearest-neighbour atoms – 12 for FCC APF: the fraction of atom-occupied volume in a unit cell
4.2198 10-22 g Unit cell volume = a3 = (0.36148)3 = 0.04723 nm3 = 4.7234 10-23 cm3 = (weight of atoms in each unit cell)/unit cell voulme = 4.2198 10-22
CN = 12 c/a = ? APF = ?
Equilateral triangle
skja_26 Diffusion in Solids 材料科学基础(英文课件)
0t0 , t1来自t2 t增加r2 r1
r1
r2 r
2020/10/25
Application to crystallization at initial stage.
d d m t 4 π D (C o r 2 C r 1 L )r 1 r 2 4 π r 1 2 D (C o r 1 C L )
C t D2 xC 2 2 yC 22 zC 2D2C
1. In Cartesian coordination system
C (D C )(D C )(D C ) t x x y y z z ifD con s C tt .D ( 2 xC 2 2 yC 2 2 zC 2)
2020/10/25
0
r 2 C 0 r
ca b r
c1
a r1
b
c2
a r2
b
a
(C2 r2
C1 r1
)r1r2
d d m t D d d C rA D 4 r 2 d d C r 4 D (C r 2 2 C r 1 1 )r 1 r 2
2020/10/25
T
T0
AC C 0
B
C
C C C0 C
dm(4r12dr1)(CL
CL)
4r12D(C
CL r1
)dt
(CL
CL)dr1
D(CL C r1
)dt
r12
2D( CL C )t CL CL
2020/10/25
Example
A 0.05cm layer of MgO is deposited between layers of Ni and Ta to provide a diffusion barrier that prevents reactions between the two metals. At 1400℃, Ni ions are created and diffuse through the MgO ceramic to the Ta. Determine the number of nickel ions that pass through the MgO per second. The diffusion coefficient of Ni ions in MgO is 9×10-12cm2/s, and the lattice parameter of nickel at 1400℃ is 3.6×10-8cm.
材料科学基础英文版课件3.6
We could then use 2 values for any of the peaks to calculate the interplanar spacing and thus the lattice parameter. Picking peak 8: 2 = 59.42º or = 29.71º (400)
3/23/2013 4
0°
S
30°
90°
° 120
中南大学
材料科学与工程
ExampleDiffraction
The results of a XRD experiment using x-rays with = 0.7107 Å (a radiation obtained from molybdenum target) show that diffracted peaks occur at the 2 angles as shown in the table. Determine the crystal structure: the indices of the plane producing each peak the lattice parameter of the material
Peak 1 2 3 4 5 6 7 8
2
20.20 28.72 35.36 41.07 46.19 50.90 55.28 59.42
3/23/2013
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中南大学
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Example 3.20
2d sin a h2 k 2 l2
SOLUTION
a h2 k 2 l 2 ) sin
T2
a1
a2
fcc: 4 atoms per UC
2材料科学基础英文版课件_
• Stress-induced non-equilibrium grain boundary
segregation – Introduction, experiment, results and discussion,
summary
• Conclusions
2019/9/24
Outline (1)
Ingot
Block 1
Sample processing and pretreatment
Pretreated samples
Aging at different temperatures for different times and quenching
Machining
2019/9/24
Experiment (2)
Applied stress
2019/9/24
2.25Cr1Mo steel
Outline (1)
• Equilibrium grain boundary segregation
– Segregation of phosphorus and molybdenum
• Introduction, experiment, results and discussion, summary
520℃
2019/9/24
Time
Heat treatment procedure
Experiment (4)
Auger electron spectrometer
2019/9/24
Auger specimen
Experiment (5)
2019/9/24
AES scanning position
– Effect of phosphorus grain boundary segregation on intergranular fracture
segregation – Introduction, experiment, results and discussion,
summary
• Conclusions
2019/9/24
Outline (1)
Ingot
Block 1
Sample processing and pretreatment
Pretreated samples
Aging at different temperatures for different times and quenching
Machining
2019/9/24
Experiment (2)
Applied stress
2019/9/24
2.25Cr1Mo steel
Outline (1)
• Equilibrium grain boundary segregation
– Segregation of phosphorus and molybdenum
• Introduction, experiment, results and discussion, summary
520℃
2019/9/24
Time
Heat treatment procedure
Experiment (4)
Auger electron spectrometer
2019/9/24
Auger specimen
Experiment (5)
2019/9/24
AES scanning position
– Effect of phosphorus grain boundary segregation on intergranular fracture
skja_06CrystallographicFormulas材料科学基础英文课件
(u1a)2 (v1b)2 (w1c)2 (u2a)2 (v2b)2 (w2c)2
For hexagonal: cos
u1u2
v1v2
w1w2
(
c a
)2
1 2
(u1v2
u2v1)
u12
v12
w12
(
c a
)2
u1v1
u22
v22
w22
(
c a
)2
u2v2
10. The volume of unit cells V
材料科学基础
Fundamental of Materials
Prof: Tian Min Bo
Tel: 62795426 ，62772851 E-mail: tmb@ Department of Material Science and Engineering Tsinghua University. Beijing 100084
For hexagonal crystals:
1 d2
4 3
h2
hk a2
k2
l2 c2
7. The length of [u v w]
L[uvw] (ua )2 (vb )2 (wc )2 2vwbccos 2uwac cos 2uvabcos
For cubic: L[uvw] a u2 v2 w2
For simple cubic (001) aaaa…… (110) abab……
shift 1 [1 10], along [1 10] 2
This sequence is called the stacking order
Ⅱ.Comparison of stacking mode of HCP and FCC
2材料科学基础英文版课件_
30 P
25 P
20
P
15
10
Mo
Mo
Mo
5
0
480
520
560
Ageing temperature (oC)
Equilibrium boundary concentrations at different temperatures
2019/10/16
40
P
P
P
30
20
Mo
Mo
Mo
10
0
480
520
Preface (3)
GS
Thermally induced NEGS
Stress induced NEGS
2019/10/16
EGS
பைடு நூலகம்
NEGS
Irradiation induced NEGS
……
NEGS induced by high
temperature deformation
Preface (4)
2.25Cr1Mo钢中磷的平衡及应力引 起的非平衡晶界偏聚
Equilibrium and Stress-induced NonEquilibrium Grain Boundary Segregations
of Phosphorus in a 2.25Cr1Mo Steel
Song Shenhua
2019/10/16
Temperature
Experiment (3)
(Austenization) (Normalization)
980℃×30min 920℃×50min
(Termper)
650℃×2h
(Ageing)
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
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
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
2020/7/3
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
2020/7/3
Examples and Discussions
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英汉科学技术词典
清华大学外语系《英汉科学技术词典》编写组 国防工业出版社, 2002
9/16/2012
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中南大学
材料科学与工程
The course of
Jingfeng LI, Huashan LIU, Zhiyi LIU, Zhenhai BAI
9/16/2012
Text book
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中南大学
材料科学与工程
中南大学
材料科学与工程
Chapter outline
1.1 What is Materials Science and Engineering? 1.2 Classification of Materials 1.3 Functional Classification of Materials 1.4 Classification of Materials Based on Structure 1.5 Environmental and Other Effects 1.6 Materials Design and Selection
HAVE YOU EVER WONDERED?
How sheet steel can be processed to produce a high-strength, lightweight, energy absorbing, malleable material used in the manufacture of car chassis? Can we make flexible and lightweight electronic circuits using plastic? What is smart material?
9/16/2012 11
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Tetrahedron of MSE
crashworthiness
抗撞性能
Composition; Strength; Weight;
toughness
韧性
Energy absorption properties; Malleability (formability)
9/16/2012
Processing
制备加工
Structure
结构
Properties
性能
Performance
服役
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材料科学与工程
Chapter outline
1.1 What is Materials Science and Engineering? 1.2 Classification of Materials 1.3 Functional Classification of Materials 1.4 Classification of Materials Based on Structure 1.5 Environmental and Other Effects 1.6 Materials Design and Selection
make existing materials better invent or discover new phenomena, materials, devices, and applications understand how to use the materials
Composition
组成
Table 1-1 (p. 12)
9/16/2012
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中南大 学 p. 12 Table 1.1
材料科学与工程
Representative examples, applications, and properties for each category of materials
Materials
9/16/2012
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中南大学
材料科学与工程
Chapter 1.
INTRODUCTION
What do materials scientist and engineer need to learn?
The principle goals of a materials scientist and engineer are to:
9/16/2012
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材料科学与工程
What is MSE
9/16/2012
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中南大学
材料科学与工程
Section 1.1
What is Materials Science and Engineering? MSE is an interdisciplinary field concerned with inventing materials and improving previously known materials by developing a deeper understanding of the microstructure-composition-synthesis, processingproperty-performace relationship.
1978-1982 198-1990 1990-1991 1992-1996 1996-1998 1999-2005 2006-2010
原中南矿冶学院 国防科技大学 原中南工业大学材料系 瑞典皇家工学院 瑞典皇家工学院 中南大学材料学院 中南大学材料学院
工学学士（有色金属合金） 工学硕士（金属基复合材料） 讲师 Licentiate（材料物理） PhD（材料物理） 教授、博导，材料学系主任 教授、博导，副院长
9/16/2012
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Section 1.2 p. 11
Classification of Materials
Metals and Alloys Ceramics, Glasses Polymers (plastics) Semiconductors Composite Materials
Figure 1.2 Application of the tetrahedron of materials science and engineering to sheet steels for automotive chassis.
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Tetrahedron of MSE
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中南大学
材料科学与工程
Tetrahedron of the MSE
Performance (P) Synthesis (s1) Processing (p) Composition (c) Structure (s2)
P = f ( c, s1, s2, p )
9/16/2012
YBa2Cu3O9-x
Composition Composition Cu O YBa YBa 22 Cu 33 O 7-x 7-x Ca Cu O YBa YBa 22 Ca 33 Cu 44 O 11 11 YSr Ca Cu O YSr 22Ca 22Cu 33O 10 10
Synthesis Synthesisand andprocessing processing How can pure, How can pure,homogeneous, homogeneous, and fine powders of and fine powders ofwell-defined well-defined stoichiometry stoichiometrybe bemade? made? How Howdo dowe wemake makelong longlengths lengths of ofwires? wires?
Physics Mathematics Chemistry Metallurgy Engineering Computation
跨学科
MSE
9/16/2012
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Section 1.1
What is Materials Science and Engineering?
The structure and composition of a material, including the type of atoms and their arrangement as viewed over the range of length scales (nano-, meso-, micro-, macro-scale). The properties of the material resulting from the atoms and their arrangement, that make material interesting or useful. The synthesis and processing by which the particular arrangement of atoms achieved. The performance of the material, that is, the measurement of its usefulness in actual conditions, taking account of economic and social costs and benefits.
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Tetrahedron of MSE
Performance Cost
What Whatis isthe thecurrent current
carrying carryingcapacity? capacity? What is What isthe thecast castof of cooling and fabrication? cooling and fabrication?