A Computational Framework for Micromechanical Modelling of WC-Co Composites

In this study, the mechanical behavior under monotonic loads of tungsten carbide‑cobalt (WC-Co) composites is investigated extensively by analyzing (1) nanoindentation tests on WC particles and Co matrix, (2) nanowires made of WC-Co composites tested in tension and (3) micropillars made of WC-Co composites tested in compression. To this end, a novel computational framework consisting of two different microplane constitutive models developed for WC and Co phases are proposed. For the Co matrix, the microplane J2-plasticity, called the model MPJ2, and for the WC particles a modified version of the microplane model M7, called the model M7WC, are employed. Furthermore, finite element meshes in 3D obtained from experimental tomography reconstructions of WC-Co composites are employed to rule out any spurious geometric features that is likely to be encountered in artificially generated meshes. After calibrating the aforementioned models, it is shown that the finite element predictions not only confirm the extensive experimental observations but also shed further light into the mechanical behavior of these composites.