Steady State Deformation and Dynamic Restoration Processes During High Strain Rate and High Temperature Deformation in Metals and Alloys

Abstract

At strain rates from 10-3 to 102 and temperature above 0.5 Tm, the flow behaviours of various metallic materials are classified into alminum type and copper type. The former has dynamic recovery as a Restoration process and the latter dynamic recrystallization. Copper type materials show smallest in the magnitude of temperature dependence and strain rate sensitivity exponent “m” value. Steady State flow Stress can be expressed as functions of product of strain rate and the reciprocal of the Arrhenius term of temperature dependence, and the values of stress exponent “n” value in it well correlates to the restoration processes of materials. It has been clarified from the observation of deformed microstructure that dynamic recrystallization as restoration process is occured soon after passing of the peak in flow curves. Finally, there has been good correlation between the deformation condition parameter and dynamically recrystallized grain diameters or dynamically recovered ones.