Effect of Rh and V Additions on Plastic Deformation Behaviour in Ni₃Nb Single Crystals with D0_a Structure

Abstract

The effect of Rh and V additions on phase stability and plastic deformation behaviour in Ni₃Nb single crystals with the D0_a structure was investigated, focusing on the slip behaviour of (010)[100], (010)[001] and (001)[100] systems in a wide temperature range between room temperature and 1200°C. The V addition induces no significant change in the critical resolved shear stress (CRSS) for (010)[100] slip at low temperatures, while the Rh addition is effective in increasing the CRSS at temperatures below 500°C and above 800°C, resulting in significant improvement of high-temperature strength. The increment of high-temperature strength is closely related to suppression of the climb motion of edge dislocations. The Rh addition also effectively increases the CRSS for (010)[001] and (001)[100] slip. The V addition was expected to enhance activation of the (010)[001] slip by reducing the SISF energy between the superpartials, but that was not achieved.