The influence of temperature and strain rate on microstructural evolution of polycrystalline copper

A ballistic testing system is introduced which allows compression tests at high strain rates within a wide range of temperature. The paper describes the experimental results obtained for polycrystalline copper at different strain rates ge (10−4 s −1 ≤ ge ≤ 104 s−1), large strains ε (up to ε ~ 1.0) and various temperatures T (22, 400 and 610 °C). Stress strain diagrams were calculated and conclusions about strain rate sensitivity were drawn. The total dislocation density is determined by X-ray diffraction. The inhomogeneity of deformation can be made visible by measuring the microhardness along the specimen axis. The data are the basis for modelling the evolution of microstructure at high strain rates and elevated temperatures.