Effect of Annealing Treatment on Ratchetting Behavior of Copper

Strain control symmetric cyclic and stress contrd asymmetric cyclic deformation tests were carried out at room temperature on unannealed hard copper and soft copper obtained by annealing treatment. The effect of annealing treatment on the microstructure and the ratchetting behavior of the copper was studied. The results show that annealing treatment increased the grain size and affected the cyclic softening/hardening characteristics of the copper. The coppers in two states showed obvious ratchetting, and the ratchetting was dependent on the level of applied stress. The increase of stress amplitude significantly affected the ratchetting strain rate in the third evolution stage of hard copper, but had little effect on the second evolution stage of soft copper. The higher the mean stress, the faster the ratcheting evolution of hard copper from the second stage to the third stage. But the effect of the mean stress on the ratchetting strain rate of soft copper in the second stage was not significant.