Chemical Engineering Basics - Engineering

Q1:

Other parameters remaining same, the recrystallisation temperature of an alloy is lowered, when

A strain rate is increased.

B grain size is increased.

C prior cold deformation is increased.

D not affected by any of the above parameters.

ANS:A - strain rate is increased.

When the strain rate is increased, it does not typically lower the recrystallization temperature of an alloy. In fact, the strain rate primarily affects the kinetics of deformation processes rather than the thermodynamics of recrystallization. The recrystallization temperature is mainly influenced by factors such as the composition of the alloy, the amount of prior cold work (deformation), and the presence of alloying elements that can affect grain boundary mobility. Increasing the strain rate affects the rate at which plastic deformation occurs in the material but does not directly impact the recrystallization temperature. Higher strain rates can lead to increased dislocation densities and higher stored energy in the material, which may influence the kinetics of recrystallization, but it does not lower the recrystallization temperature itself. Therefore, the correct explanation is that increasing the strain rate does not lower the recrystallization temperature of an alloy.