Effect of Modes of Deformation by Cold Rolling on Microstructure, Texture and Mechanical Properties of Ni-16Cr and Ni-16Mo Alloys

Abstract

The effect of modes of deformation (unidirectional, two-step and multi-step-cross rolling) by cold rolling on microstructure, texture, and mechanical properties of the Ni-16Cr and Ni-16Mo alloys has been discussed in this work. The overall texture intensities of both the alloys are always strong in unidirectional mode of cold rolling after 90% deformation as compared to two-step and multi-step cross rolling. There is a strong bearing between the overall texture intensity and intensity of the Brass ({0 1 1}〈2 1 1) component of 90% deformed sheets irrespective of the modes of deformation and alloy system. The evolution of {111}-fibers is an important phenomenon during cold rolling of both the alloys which appear to be stable in a particular range of overall intensity of ODF (Orientation Distribution Function) and this range varies with modes and extent of deformation. The alloy Ni-16Mo exhibits better mechanical properties than the alloy Ni-16Cr in 90% deformed condition. The measured values of relative resolved shear stress corresponding to the strongest texture present in the 90% deformed sheets well explain the variation in uniform elongation with change in modes of deformation. Both the alloys in highly (90%) deformed condition display two-slope behavior and follow Ludwigson (with negative deviation at low strain) and Voce relationships. The instantaneous work hardening curves of both the alloys show continuous decrease of work hardening till it attains saturation in the last stage of plastic deformation before necking. The linear portion of this last stage has been explained using Kock-Mecking-Estrin analysis and correlated with overall uniform elongation. © ASM International 2023.