Stress–strain behaviors of cermets with various binder contents and residual thermal stress states

Abstract

The stress-strain behaviors of WC–Co cermets with various binder contents were investigated, in which the residual thermal stress (RTS) was taken into account. The effects of binder content and WC grain morphology on the RTS and strain responses under applied stress were quantified by finite element modeling based on the real microstructures of cermets. It shows that the RTS of both the hard matrix and ductile binder phases are linear functions of the binder content. High-level RTS is concentrated in the WC region close to WC/WC grain boundaries adjacent to the Co phase, and in the Co region close to the WC/Co interface, respectively. In the cermets with RTS, the accumulation rate of strain partitioning and strain localization in WC–Co cermets decreases with the decrease of Co content. It is found that increasing the proportion of thin Co layers parallel to the compression direction is beneficial to simultaneously strengthening and toughening cermets with low Co contents. This study provides access and mechanisms for modulating RTS distribution to achieve excellent comprehensive mechanical properties of cermets with various binder content.