Prediction of deformation behavior in pure aluminum at high temperatures by constitutive law including effective stress

Constitutive equation was proposed for high-temperature deformation of pure aluminum based on the supposition that 1. there exists effective stress, 2. work-hardening rate is almost identical to that of room temperature, 3. work-hardening rate is uniquely determined by internal stress and recovery rate are determined by internal stress and temperature. The constitutive equation was applied to stress change test, strain rate change test and stress relaxation test in order to obtain strain (or stress)-time curve in these tests. It was supposed that there is a transition time of 0.02 s when stress or strain rate is abruptly changed in these tests. The strain (or stress) -time curve obtained by computer simulation agreed very well with experimental results in literature, which suggests that the current theory is doubtful that effective stress does not exist in high-temperature deformation of pure aluminum.