Test: Mechanical Properties of Materials - 2 - Mechanical Engineering MCQ

The stress required to cause the metal to flow plastically to any given strain.

Chances of plastic deformation is negligible for a rotating shaft if the system is balanced.

(Bauschinger effect and hysteresis loop) Due to stress loading unloading, the yield stress in tension gets increased and yield stress in compression gets decreased. This decreasing of yield stress in compression is the Bauschinger effect. 

it is a property of material allows it to expand in all directions without rupture. A malleable material has to be highly plastic, though it may not posses high stress. This property is of great use in processes such as forging, hot rolling, etc.

Contents of alloys improve or decrease the hardness and strength of materials. Finer grain sizes improve the strength of the material. Imperfection and defects reduce the strength of the material. Shape, however, has little or no effect on the material.

The poisson's ratio is related to modulus of elasticity as Y=3B (1 − 2σ).
Since stress is same for Y and B, we get, dL/L = dV/3V (1 − 2σ)
⟹dV = 3V(dL/L)(1 − 2σ)
As σ is increased, dV decreases.