Mechanical Behavior of Metals Crystal Structure - Mechanical Engineering (MCQ) questions and answers

1)   Match the following group 1 items (crystal structures) with group 2 items (average number of atoms per unit cell) and select the correct option

1. Simple cubic crystal structure ----------------- A.  2
2. Body centered crystal structure --------------- B.  6
3. Face centered crystal structure ---------------- C.  1  
4. Hexagonal close packed structure ------------ D.  4


a. 1 – A, 2 – C, 3 – D, 4 – B
b. 1 – C, 2 – A, 3 – D, 4 – B
c. 1 – B, 2 – A, 3 – C, 4 – D
d. 1 – D, 2 – A, 3 – B, 4 – C
Answer  Explanation 

ANSWER: 1 – C, 2 – A, 3 – D, 4 – B

Explanation:
No explanation is available for this question!


2)   What is meant work hardening process?

a. Ductile materials are deformed plastically at temperatures below crystalline temperatures which increases strength and hardness of the material
b. Ductile materials are deformed plastically at temperatures above crystalline temperatures which increases strength and hardness of the material
c. Ductile materials are deformed plastically at crystalline temperatures which increases strength and hardness of the material
d. None of the above
Answer  Explanation 

ANSWER: Ductile materials are deformed plastically at temperatures below crystalline temperatures which increases strength and hardness of the material

Explanation:
No explanation is available for this question!


3)   Body centered cubic structure has an atomic packing factor equal to

a. 0.74
b. 0.68
c. 0.52
d. None of the above
Answer  Explanation 

ANSWER: 0.68

Explanation:
No explanation is available for this question!


4)   In which type of point defect, positive and negative ions are missing from the crystal?

a. Vacancy defect
b. Interstitial defect
c. Schottky defect
d. Substitutional defect
Answer  Explanation 

ANSWER: Schottky defect

Explanation:
No explanation is available for this question!


5)   Energy required for deformation can be calculated using the formula

a. E = L2 G b
b. E = L G b2
c. E = L (Gb)2
d. E = L G b
Answer  Explanation 

ANSWER: E = L G b2

Explanation:
No explanation is available for this question!


6)   Which of the following statements is/are true for cold working process?

1. Cold working process does not provide good surface finish
2. Cold working process produces internal stress in a metal
3. Fatigue strength of metals can be improved
4. Cold working process cannot take place below recrystallization temperature


a. statement 1 and statement 2
b. statement 2 and statement 3
c. statement 3 and statement 4
d. all the above statements are true
Answer  Explanation 

ANSWER: statement 2 and statement 3

Explanation:
No explanation is available for this question!


7)   Why are internal stresses not produced in hot working process?

a. Micro structures undergo distortion
b. Hot working process do not undergo recrystallization
c. Hot working process undergo recrystallization
d. None of the above
Answer  Explanation 

ANSWER: Hot working process undergo recrystallization

Explanation:
No explanation is available for this question!


8)   What is meant by Frenkel defect?

a. defect in which interstitial position is occupied by missing atoms
b. defect in which positive and negative ions are missing
c. defect in which interstitial position is occupied by extra atom in the crystal without disorganizing the parent atom
d. none of the above
Answer  Explanation 

ANSWER: defect in which interstitial position is occupied by missing atoms

Explanation:
No explanation is available for this question!


9)   Which among the following is known as Schmid's factor?

a. (cos2 α) x (cos2 β)
b. (cos α) x (sin β)
c. (sin α) x (sin β)
d. (cos α) x (cos β)
Answer  Explanation 

ANSWER: (cos α) x (cos β)

Explanation:
No explanation is available for this question!


10)   When are the slip lines observed?

a. after plastic deformation
b. before plastic deformation
c. after mechanical working
d. after annealing
Answer  Explanation 

ANSWER: after plastic deformation

Explanation:
No explanation is available for this question!


1 2