Numerical modeling of the progressive damage in the microstructure of WC-Co hardmetals under fatigue loading

Abstract

The study presents a framework of simulating the progressive damage under cyclic loading with the stress ratio R=0.1 in the WC-Co hardmetals at meso- and microscale by finite element method. A two-and-a-half-dimensional microstructure model is created based on electron backscatter diffraction micrographs. It is able to capture the major microstructural characteristics of this material and preserve the local crystalline orientation. A set of anisotropic elasticity constants is adopted for brittle WC phase, and elasto-plastic material parameters for the ductile binder matrix are derived from fundamental static and dynamic testing conducted on macroscopic binder-like alloy specimens. Proper failure models are applied for both phases to represent their respective failure mechanisms. Taking the residual stresses as an initial condition, the study also introduces a method to investigate the influence of residual stresses on the fatigue performance of hardmetals. The numerical implementation is realized with user subroutines in the commercial finite element solver Abaqus.