New insights into the development of microstructure and deformation texture in nickel–60 wt.% cobalt alloy

Abstract

The present study investigates the critical role of deformation twinning and Bs-type shear bands in the evolution of deformation texture in a low stacking fault energy Ni–60Co alloy up to very large rolling strain (εt≈4). The alloy develops a strong brass-type rolling texture, and its formation is initiated at the early stages of deformation. Extensive twinning is observed at the intermediate stages of deformation, which causes significant texture reorientation towards α-fiber. A pseudo-in-situ electron back-scattered diffraction technique adopted to capture orientation changes within individual grains during the early stages suggests that twinning should be subsequently aided by crystallographic slip to attain α-fiber (〈110〉||ND) orientations. Beyond 40% reduction, deformation is dominated by Bs-type shear bands, and the banding coincides with the evolution of 〈111〉||ND components. The volume fraction of shear bands is significant at higher strains, and crystallites within the bands preferentially show 〈110〉||ND components. The absence of the Cu {112}〈111〉 component in the initial texture, and subsequently during rolling, indicates that, for the evolution of a brass-type texture, the presence of the Cu component is not a necessary condition. The final rolling texture is a synergistic effect of deformation twinning and shear banding.