X-Ray Stress Measurement of WC-Co Alloys

Abstract

The X-ray diffraction method was applied to measure the applied and residual stress in WC-Co alloys with various cobalt contents. The X-ray diffractions of WC 112 and Co 311 by Fe-Kα radiation were used for stress determination. The mean stress in each phase increased linearly with the applied stress; the stress in WC phase was larger than that in Co phase at the same strain. The macrostress calculated from the phase stresses by using the rule of mixture was nearly equal to the applied stress. The theoretical analysis based on the self-consistent model of elastic deformation of composites agreed fairly well with the experiments. The compressive residual stress measured on the ground surface was larger than that on the lapped surface, and decreased with increasing Co volume fraction. Annealing at 800 and 1000°C greatly reduced the compressive residual stress. The residual microstress after annealing was compression in WC phase and tension in Co phase.