A numerical approach to investigate the microstructural damage of hard cemented carbides

Hard cemented carbides are frequently used in applications requiring high hardness and wear resistance. In machining process, around 90% of cutting tools are made of tungsten carbide (WC) with different binder contents of cobalt (Co). In this application, the WC-Co is subjected to different wear mechanisms such as abrasion, adhesion, and diffusion. Several models have been developed in the literature to estimate the tool life but only few of them consider the microstructure of cutting tools. At this scale, intergranular and transgranular fracture, which highly contribute to the overall damage of the tool, can be observed. In this work, a numerical modelling based on a finite-element approach has been developed to investigate the microstructural damage as a precursor to the wear process. The aim is to establish a wear model for machining that takes into account the microstructure of the WC-Co tool. This work is a first step of this model. The microstructure of a representative elementary volume (REV) of WC-Co is generated by an algorithm based on a Voronoi tessellation. To reproduce the mechanical behavior of the WC and Co phases, Drucker-Prager and Johnson-Cook yield criteria have been used. In addition, the damage behavior of the WC/WC and WC/Co interfaces and the WC and Co phases have been simulated by cohesive interface and ductile damage models, respectively. The microstructure has been subjected to different contact pressures on one of its faces by a sliding rigid body. Microstructure damage was found to increase progressively with increasing contact pressure. First qualitative comparisons of the numerical results with experiments from the literature confirmed the good consistency of the model with experimental observations.