Exploring the origin of wear in cemented carbides via molecular dynamics simulations

Abstract

In this work, the experimentally observed tribological phenomena of WC-Co cemented carbides were interpreted on the atomic scale using molecular dynamics simulations. It was demonstrated that the friction-induced deformation was mainly coordinated by dislocations slip in both Co and WC phases, along with the local rotation of WC grains adjacent to the Co binder. The dislocation motion within the subsurface Co phase was crucial for the continuous transfer of stress across WC/Co interfaces. The fracture of WC grains, which frequently occurs in various friction processes, was found to result from interactions between the internal partial dislocations. This caused formation of atomic-scale micro-voids early at the intersection. Significantly higher tensile stress existed at the WC/WC grain boundaries, which resulted in a higher risk of intergranular cracking compared to that at the WC/Co interfaces during the friction process. The findings in the present study facilitate to understand the tribological behavior of a variety of cermet materials hence to improve their wear resistance.