材料物理导论 试卷及参考答案-试卷及参考答案-Test4 B

河北大学课程考核试卷
—学年第学期级应用物理物理专业（类）
考核科目材料物理导论课程类别考核类型考试考核方式开卷卷别 B （注：考生务必将答案写在答题纸上，写在本试卷上的无效）
1.Choice (30 points, 3 points for each question)
1). Point defects in metal make resistance:
A. increase
B. decrease
C. invariant
2). Generally speaking, the direction of dislocation movement is:
A. similar to the direction of crystal slip;
B. the vertical direction of dislocation line;
C. the parallel direction of dislocation line;
3). There are usually solute atoms or impurity atoms in metal, whose existence:
A. always increase lattice constant;
B. always decrease lattice constant;
C. may increase or decrease lattice constant
4). Which is the driving force of atom diffusion in solid metal:
A. Concentration gradient;
B. Chemical potential gradient;
C.Diffusion activation energy
5). Work hardening is a useful strengthening method, but its drawback is:
A. suitable for bi-material only;
B. not suitable when material heated at high temperature;
C. suitable for single crystal only
B-4-1
6). The critical resolved shear stress of single crystal is related to .
A. external force related to the orientation of slip system;
B. tensile yield stress
C. metal type and purity
7). In high-temperature recovery stage, when metal sub-structure changes:
A. Dislocation density increases;
B. Dislocation pile-up happens;
C. Edge dislocation constitutes sub-structure though climbing and slipping
8). Edge dislocation has a fixed slip plane, while screw dislocation does not have.
A. Ture
B. False
9). Vacancy diffusion is the process of atomic migration, atoms arranged in lattice jump to the interstitial site in the surrounding, and then return to another vacancy point in space through the moving of atoms in space.
A. True
B. False
10). Supercooling required for nucleation of pure metal crystallization is always greater
than dynamic supercooling.
A. True
B. False
2.Fill-in & Short Answer (30 points, 2 points for each blank & 5 points for each
question)
1). Four families of engineering materials include . The materials can be divided into .
2)．The influence factors on diffusion：.
B-4-2
3)．Determine the crystal face index of two planes and orientation index of body diagonal as shown in the right
figure:
4). What is spontaneous polarization? How to understand
the ferroelectric properties of materials? Illustrate the
applications of ferroelectrics. 5). Direct current sputtering process could only realize a conductor material deposition, while radio freqency sputtering could realize not only conductive materials deposition, but also dielectrics deposition. How to explain this phenomenon?
6). Explain the reason for the formation of upper yield point and lower yield point in yield phenomenon.
7). If the direction of a dislocation line is defined as a reverse original direction, Burgers vector will change or not? How about the properties of dislocation type? Whether the dislocation type of points on the dislocation ring are the same?
3. Calculation (40 points)
1). It needs 104.675 kJ energy to formation 1 mol vacancy in iron. How many times do the vacancy number increased when temperature goes up to 850 o C from 20 o C? (10 points)
2). There is a plastic film which is used to separate hydrogen from airflow. When it comes to stable state, hydrogen concentration on one side of the film is 0.25mol/m 3, while it is 0.025mol/m 3 on the other side. Film thickness is 100 micron. Hydrogen flux
X Y
Z B-4-3
through plastic film is 2.25 ⨯10-6mol/(cm3⋅s). Please calculate diffusion coefficient of hydrogen. (10 points)
3.Calculation (40 points, 20 points for each question)
1). Solid solution phase diagram is shown in
the following figure. According to phase
diagram to determine:
(a) If the component of alloy is
w(B)=40%, what is the first composition
will be solidified?
(b) If the firstly-solidified composition is
w(B)=60%, what is the component of
the alloy?
(c) If the component of alloy is w(B)=70%,
what is the last-solidified composition?
(d) The component of alloy is w(B)=50%. At a certain temperature, liquid containing
w(B)=50%, solid containing w(B)=80%, what is the respective fraction of liquid and solid?
B-4-4。