Residual stress and stress distribution in a WC-Ni composite

Abstract

The differential thermal stress state in a WC-15.6wt.%Ni cemented carbide composite has been studied using neutron powder diffraction. Absolute stress values have been obtained from the difference in WC cell parameters in a stress-free, loose WC powder and the WC phase in the composite over the temperature range 20–700 K. In addition, the stress distribution in the WC phase was determined by analysis of WC peak breadths in the reference powder and the composite. The peak breadths were corrected for particle size effects using a procedure based on the integral peak breadth method of particle size-strain analysis. The resultant full width at half-maximum values of the elastic strain distribution indicate that a broad range of strain, and thus stress, is present in the carbide phase of the composite. The distribution is centered on an average compressive stress and ranges from very compressive to very tensile values. The stress distribution results are consistent with prior results in other WC-Co and NbC-Co cemented carbides.