Annealing-induced softening of copper and molybdenum for high strain rate deformation

Abstract

The effect of annealing on the high strain rate deformation properties of copper and molybdenum was studied. Samples were extracted using spark erosion and were annealed under various conditions. High strain rate stress-strain curves at ~700 s −1 and 1500 s −1 were measured using a split Hopkinson pressure bar. Recrystallization occurred for the copper and molybdenum at annealing temperatures of 300°C and 1200°C, respectively, and resulted in a significant softening of the samples compared to their unannealed state. Generally, copper and molybdenum are annealed at much higher temperatures and it is suggested that lower temperature annealing may provide cost savings during the manufacturing processes.