EFFECT OF TEMPERATURE ON THE HIGH STRAIN-RATE FRACTURE CHARACTERISTICS OF DUCTILE METALS

Induction heating has been employed to rapidly raise the temperature of ferrous specimens prior to testing at strain-rates > 10(3) s(-1). The results show a general tendency for the ductility of a specially-processed pure iron to decrease with temperature over the range tested (20-400 C). Based on the experimental data and the results of numerical simulations of the experiment, an empirical fracture model has been derived for the iron which gives fracture strain as a function of state-of-stress and temperature. Recently, the induction heating technique has been extended to nonferrous materials. High strain-rate tests on 99.9% pure copper revealed no significant effect of temperature on ductility over the range of start temperatures employed (20-300 C).