Cold deformation of a nickel-base superalloy

Abstract

An analysis of the low deformation level (less than 5% strain) characteristics of polycrystalline samples of an engineering alloy is presented. The material used was a wrought nickel-base superalloy, Nimonic 80 A, the microstructure of which had been modified in a controlled way to give a related series of phase distributions. This allowed the roles of the various microstructural constituents to be assessed. Selected mechanical property data were correlated with the deformation microstructures, as determined by transmission electron microscopy. The presence of carbide particles on the grain boundaries was found to affect both the observed deformation patterns and the work-hardening rate. However, although the majority of the dislocation nucleation events occurred at the grain boundaries, the stress-strain characteristics were more sensitive to intragranular than to intergranular microstructures.