High temperature dynamic characterization of an aluminum alloy with modified Kolsky bar

摘要

In this work, the dynamic mechanical behavior of AA2219 aluminum alloy was investigated at high temperature. Experiments were carried out at a strain rate of 4500 s~(-1) and in the temperature range from room temperature to 0.75 T_m (T_m = melting point). These experiments were conducted using a modified compression Kolsky bar. A non-contact type spot heater was used to heat up the specimen to the desired temperature in a short time (< 60 sec). An electro-pneumatic system was used while performing the experiments, which bring the pressure bars in contact with specimen just before the arrival of stress wave. A cold contact time of 35-45 milliseconds was maintained during the experiments. The material stress-strain and strain hardening behavior showed significant dependence on temperature at high strain rate and flow stress decreased with increase in temperature due to thermal softening. A power law relationship was observed between flow stress and temperature.