Yield and Strength Properties of Metals and Alloys at Elevated Temperatures

Abstract

The main driving force behind high-strain-rate testing is the need to obtain values for the parameters in the various material constitutive models used in the numerical simulation of the impact or shock response of materials and structures. Information about the high-strain-rate properties of materials at elevated temperatures is important for problems such as penetration and high-rate metallurgical treatment by cutting or forging, since the transient loading processes are accompanied by irreversible heating. The knowledge of the temperature dependencies of dynamic responses of materials would also help us better understand the nature of thermomechanical instabilities as manifested by the formation of shear bands. The existing theory on formation of shear bands is based on a competition between the strain hardening and the thermal softening of material during an adiabatic deformation process. There is a general agreement that the tendency to form adiabatic shear bands increases when the strain hardening decreases and the thermal softening increases. Since high strain rates create the adiabatic conditions for the induced deformation, shear banding is usually associated with impact loading.