Microstructure, Texture, and Orientation-Dependent Flow Behavior of Binary Ni-16Cr and Ni-16Mo Solid Solution Alloys

Abstract

This work describes microstructure, texture, and orientation-dependent flow behavior of Ni-16Cr and Ni-16Mo alloys in hot rolled and annealed condition. The high and low stacking fault energy values associated with Ni-16Cr and Ni-16Mo result in partial recrystallization after recovery and presence of twins in recrystallized grains, respectively. Both the alloys display two slopes in the true plastic stress–strain curves and follow Ludwigson relation, however the deformation mechanisms of both the alloys associated with two slopes are different. The low-strain regime of flow curves of the alloy Ni-16Cr is associated with uniform and finely spaced slip lines within the grains along with very small fraction of strain localization. On the other hand, a few slip lines appear to cross the grain boundaries in high-strain regime with a favorable angular deviation between adjacent grains along with large fractions of strain localization (2 to 5 deg low-angle grain boundary). On the other hand, the low-strain regime of the alloy Ni-16Mo is related to the presence of uniformly and finely spaced slip lines and small fractions of both the deformation twins as well as strain localization. The main features of high-strain regime of the alloy Ni-16Mo exhibit large volume fractions of deformation twins and strain localization along with few coarse penetrating slip lines across the grain boundaries. Sample orientation-dependent ductility of both the alloys has been explained based on dislocation storage capacity and dynamic recovery coefficient using Kock–Mecking–Estrin analysis.