THE INFLUENCE OF TEMPERATURE AND STRAIN-RATE ON MICROSTRUCTURAL EVOLUTION OF POLYCRYSTALLINE COPPER

A ballistic testing system is introduced which allows compression test s at high strain rates within a wide range of temperature. The paper d escribes the experimental results obtained for polycrystalline copper at different strain rates (epsilon) over dot (10(-4) s(-1) less than o r equal to (epsilon) over dot less than or equal to 10(4) s(-1)), larg e strains epsilon (up to epsilon similar to 1.0) and various temperatu res T (22, 400 and 610 degrees C). Stress strain diagrams were calcula ted and conclusions about strain rate sensitivity were drawn. The tota l dislocation density is determined by X-ray diffraction. The inhomoge neity of deformation can be made visible by measuring the microhardnes s along the specimen axis. The data are the basis for modelling the ev olution of microstructure at high strain rates and elevated temperatur es. (C) 1997 Elsevier Science S.A.