Recovery and recrystallization during high temperature deformation of α-iron

The high temperature deformation of vacuum-melted iron and zone-refined iron has been studied in the temperature range 500° to 800°C over a wide range of strain rates in torsion. Changes in stress-strain behavior and metallographic observations show a transition in the dynamic restoration process from recovery at high stresses to recrystallization at low stresses. The results are discussed in terms of a model for dynamic recrystallization. It is shown that the dependence of the critical strain for the onset of recrystallization on experimental conditions is the most important factor in determining the deformation characteristics.