Plastic Deformation

· The temperature dependence of the hardness decrease due to recrystallization is shown.
· This process is diffusion controlled, and the recrystallization rate may be determined from the time to decrease the hardness by 50 % at any given temperature:
Rate = (1/t_50%) = A exp(- ΔE/kT)
where T is the Kelvin temperature, ΔE the activation energy, and A is a material constant.

From: Barrett, Nix & Tetelman,
"The Principles of Engineering Materials,"
Prentice Hall (1973)

· Hot working materials above their recrystallization temperatures permits recrystallization to occur while strain hardening is taking place.