DYNAMIC RECRYSTALLIZATION IN NICKEL AND NICKEL-IRON ALLOYS DURING HIGH TEMPERATURE DEFORMATION

The high temperature deformation of nickel and three nickel-iron alloys has been studied between 0.6 and 0.9 Tm over a wide range of constant strain rates in torsion. It is established from metallographic and flow stress observations that dynamic recrystallization occurs at strains greater than a critical value and results in a recrystallized grain size which is determined entirely by the flow stress. The kinetics of dynamic recrystallization are discussed and shown to be in agreement with experimental observations. It is concluded that the activation energy for deformation is determined by recrystallization and that recrystallization is periodic at low stresses but becomes continuous with increasing stress. © 1969.