Dynamic constitutive relation and macro/micro failure mechanism of fine-grained WC-Co composite

As the core of an armour-piercing projectile, it is crucial to provide a microscopic perspective to elucidate the macroscopic mechanical responses of fine-grained WC-Co composite under dynamic loadings. This study investigated the dynamic constitutive relation and macro/micro failure mechanisms of fine-grained WC-Co composite. Results showed that the compressive and tensile strengths increase with the strain rate influenced by the inertia effect of crack propagation and the presence of the Co phase. The strain rate dependency mechanism of the composite was obtained by comparing it with typical ceramic materials. Macro-crack propagation and distribution were discussed under different stress states in dynamic compression and Brazilian splitting tests. Microscopic failure mechanisms were obtained by SEM technique, revealing that the Co phase creates numerous localized dimple fractures and improves the plastic deformation of the WC-Co composite.