Engineering Questions with Answers - Multiple Choice Questions

Materials Science MCQ’s – Lattice Strain

1 - Question

Which of the following is not a lattice strain due to dislocation?
a) Tensile lattice strain
b) Compressive lattice strain
c) Shear lattice strain
d) Torsional lattice strain
View Answer Answer: d
Explanation: Due to the movement of dislocation in a material tensile lattice strain, compressive lattice strain and shear lattice strain are felt by the neighboring atoms in the lattice.

2 - Question

When atoms are deformed approximately what fraction of deformation energy is retained internally?
a) 5%
b) 10%
c) 15%
d) 20%
View Answer Answer: a
Explanation: When a metal is plastically deformed, the atoms inside the lattice retain approximately 5% of the deformation energy.

3 - Question

For which of the following dislocation the strain is pure shear?
a) Screw dislocation
b) Jog dislocation
c) Mixed dislocation
d) Edge dislocation
View Answer Answer: a
Explanation: In screw dislocation only, pure shear stress is felt by the body while in edge dislocation, jog dislocation and mixed dislocation, other types of lattice strains also exist.

4 - Question

Which of the following will decrease lattice strain?
a) Line defects
b) Point defects
c) Dislocation
d) Heating the material
View Answer Answer: d
Explanation: When a body is heated the strain on the body decreases whereas it increases when defects like line defects, point defects and dislocation are present in the lattice.

5 - Question

How high can dislocation density of a material be when it is heavily deformed?
a) 1010 mm-2
b) 109 mm-2
c) 1011 mm-2
d) 1012 mm-2
View Answer Answer: a
Explanation: The dislocation density of a material increases with increase in deformation and the heavily deformed material will have dislocation density up to 1010 mm-2.

6 - Question

Two edge dislocation on same slip plane and the same sign will ________
a) Exert attractive force
b) Exert no force
c) Exert repulsive force
d) Exert shearing force
View Answer Answer: c
Explanation: When two dislocations are of the same sign and are located on the same slip plane they exert a repelling force on each other.

7 - Question

Dislocation annihilation occurs when two dislocations of different signs meet each other on the same plane.
a) True
b) False
View Answer Answer: a
Explanation: When two dislocations of opposite sign are on located on same slip plane the two dislocations exert an attractive force and then they will start moving towards each other on meeting dislocation annihilation takes place.

8 - Question

Shear strains are observed in the vicinity of the edge dislocation.
a) True
b) False
View Answer Answer: a
Explanation: Along with tensile and compressive strains, in edge dislocation shear strains are also observed in the neighboring regions of the dislocation.

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