Determination of parameters for thermally activated glide from stress- strain curves at different temperatures and strain rates

Abstract

Material parameters describing both steady state and primary creep deformation by thermally activated dislocation glide were investigated as a function of temperature for polycrystalline copper by determining stress-strain curves at different rates. Dynamic rather than static testing had to be used to eliminate effects due to other deformation mechanisms at the higher temperatures. Activation energies and 0 K flow stresses involved in both steady state and primary creep equations were independent of temperature. The flow stress terms defining ’equilibrium’ stress-strain curves required for the primary creep formulation were linear functions of temperature. This indicates that primary creep due to thermally activated glide at different temperatures may be estimated from tests at a single temperature.