Question

1-which one does not correspond to mechanism strengthening?

a-alloying or dopping with impurities

b-grain-size reduction

c-grain growth

d-strain hardening

2-in polycrystals, the grains with the lowest resolved shear stress always yields firts.

true or false

3-resolved shear stress is the result of the application of simple shear stress to a piece of material.

true or false

4-decrease on strain hardening?

a-percent enlogation

b-elastic modulus

c-yield strenght

d-hardness

5-which term is different from other options?

a-strain hardeninh

b-dislocation hardening

c-cold working

d-work hardening

Answer 1

1.C

Grain Growth

Grain Growth take place after recrystilisation and recovery phenomenon. Strength of material decreases little by grain growth while ductility improves.

Rest all three phenomena results in increase in strengths.

2. True

The grains with the lowest resolved shear stress always yields firts in polycrystiline materials.

3. True

Resolved shear is due to result of simple shear stress on a material.

4.A

percent elongation

Starin hardening increase strength, elastic modulus & hardness but decreases ductility.

Hence percent elongation also decreases.

5. B

Dislocation Hardening

Work hardening, strain hardening or cold working are same phenomena.