On the Conversion of Plastic Work into Heat During High-Strain-Rate Deformation

Heat generation in metals during high-strain-rate plastic deformation was investigated. Experiments were designed to measure the partition of plastic work into heat and stored energy during dynamic deformations under adiabatic conditions. A Kolsky pressure bar was used to determine mechanical properties at high strain rates while a servo-hydraulic material testing system was used at low strain rates. For dynamic loading, in-situ temperature changes were measured using a high-speed infrared detector. The dependence of the fraction of plastic work converted to heat on strain and strain rate was determined for an aluminum 2024-T3 alloy and alpha-titanium. The flow stress and the fraction of plastic work converted to heat for 2024-T3 aluminum alloy were found to be a function of strain but not of the strain rate while they were found to be strongly dependent on strain rate for alpha-titanium.