THE HIGH STRAIN-RATE FRACTURE CHARACTERISTICS OF DUCTILE METALS AT ELEVATED AND SUB-AMBIENT TEMPERATURES

High strain-rate tensile tests have been carried out on pre-notched sp ecimens of OFHC copper and Remko iron at both elevated and cryogenic t emperatures. When properly expressed as a function of stress triaxiali ty at the centre of the notch (as predicted by numerical simulations o f the experiment), the ductility of copper was found to be independent of temperature over a range from -190 degrees C to 300 degrees C. The specially-processed Remko iron was found to undergo a ductile-to-brit tle transition at a temperature dependent on the stress triaxiality an d the particular batch of the material. Otherwise the fully ductile st rains-to-failure (when expressed as a function of stress triaxiality) for iron were found to decrease with increasing temperature up to 400 degrees C; this being the maximum temperature tested.