Effect of deformation mode on hot deformation characteristics and microstructural evolution in Cu-Cr-Zr-Ti alloy

Uniaxial (UC) and plane strain compression (PSC) tests were performed on the Cu-Cr-Zr-Ti alloy specimens to investigate the effect of the deformation mode on the stress-strain response, work hardening behaviour and microstructural evolution in the alloy. These tests were performed at a strain rate of 1 s-1 and in the temperature range of 700-800 degrees C to impart von Mises equivalent strains of 0.15, 0.45 and 0.69. The alloy showed a regime of constant work hardening rate in the recovery stage before transitioning to the steady state under UC as opposed to PSC in which the alloy exhibited a smooth transition from recovery stage to the steady state stage. The microstructures evolved under UC consisted of randomly oriented equiaxed grains delineated by high angle boundaries (HABs) with high fraction of sigma 3 boundaries. On the other hand, under PSC a very strong {001}100 cube texture evolved with increase in strain. This strong cube texture was ascribed to the evolution of and the increased stability of cube-oriented elongated substructures observed in the deformed matrix. The difference in the work hardening behaviour was thus attributed to the higher evolved sigma 3 fraction under UC and the cubeoriented elongated substructures evolved under PSC. The dynamically recrystallized grains fraction calculated from area of grain orientation spread (GOS) map with GOS < 2o was found to be lower in the alloy under PSC owing to the presence of high orientation gradients within the evolved cube-oriented elongated substructures.