Mechanical behavior of cermets with different morphology of ceramic grains

Abstract

It is challenging to describe quantitatively the effects of ceramic grain morphology on the stress and strain distributions in the cermet materials under different loading conditions. Here the dependence of the distribution of residual thermal stress (RTS) in the as-prepared cermets and its mechanical behavior under external stress on the morphology of ceramic grains were quantified and resolved by modeling and experimental studies, using WCCo cermets as a typical example. A model was proposed to visualize the strain localization and reveal the mechanisms of the initiation and propagation of micro-cracks in the microstructure of cermets under varying loads, and the calculation results were verified by experimental measurements. It was discovered that the effects of WC grain morphology on the mechanical behavior and failure mode of cermets are distinctly different under tension or compression loading conditions, whose mechanisms were disclosed based on detailed analysis of micro-scale strain responses. The results indicate that it is feasible to modulate the strain distribution by tailoring the grain shape character for adapting to external loading, hence optimizing the material mechanical behavior.