High temperature deformation and in situ fracture measurements to understand grain size/binder effects in hardmetals

The aim of the project is to examine the role of microstructure and binder chemistry on interface properties in crack growth. Different types of WC/WC grain boundaries (in terms of CSL) making up the material have been identified. Work is being done to fabricate double cantilever beams (DCB) around these boundaries with the objective of understanding interface properties. DCB tests have been performed on WC single crystals and large WC grains (~20-100 microm) as a basis for interface study: this is to be used as an opportunity to determine the surface energies of WC crystallographic planes and compare with density functional theory calculations from the literature. Future work will be concerned with studying WC/WC boundaries with cobalt infiltration or chromium layers. WC/WC cobalt infiltration occurs during creep due to grain boundary sliding. Chromium is added to inhabit grain growth.