The static restoration of copper after monotonic or cyclic torsion at 673 K

This paper presents an analysis of the effect of the strain path on the hot flow curves and on the post-deformation static restoration of copper. Hot working was completed either through monotonic (continuous) or cyclic (reversed) torsion with strain amplitude of 0.05, at a temperature of 673 K (400 °C) and a strain rate of 0.1 s−1. The steady state flow stress under cyclic processing was lower than the same stress for monotonic torsion. Softening after straining was analyzed through the double hit technique, where the test is stopped for various periods of time, followed by reloading. Static restoration kinetics after monotonic torsion led to fast and extensive softening, which reached 95% after 100 s. Static softening after cyclic torsion was much slower and more limited than after monotonic torsion and was associated with the occurrence of static recovery as the dominant softening mechanism.