Statistics-based numerical study of the fatigue damage evolution in the microstructures of WC-Co hardmetals

Abstract In industrial applications, hardmetal tools are often exposed to fatigue loads. This paper proposes a micromechanics-based numerical approach for evaluating the fatigue performance of WC-Co hardmetals. Because the mechanical response of the material is sensitive to the coexisting toughening and damage mechanisms of the ductile binder matrix, this study employed a Chaboche model to precisely present the kinematic hardening behavior and describe the material plasticity of the binder phase. The progressive fracture in the microstructure is modeled by an implicit damage mechanics model implemented in the commercial solver Abaqus/Standard. The numerical study successfully simulated different stages of the fatigue failure process by modeling the damage behavior in the microstructure and reproducing the compromising roles of the ductile binder under the fatigue regime. In addition, the study also emphasizes the need to view fatigue behavior from a statistical perspective owing to the high level of microstructure heterogeneity. By studying the cyclic responses of 50 representative volume element models converted from real scanning electron microscope images, the study revealed how the microstructural characteristics of the hardmetal interact with the imposed external loading and how these two factors jointly determine the load-bearing capacity of the material.