Molecular dynamics simulation of shock-induced plastic deformation and spallation behavior of Cu/Cu64Zr36 crystalline/amorphous composites

Abstract

Molecular dynamics (MD) simulations were performed to study the shock-induced plastic deformation and spallation failure of Cu/Cu₆₄Zr₃₆ crystalline/amorphous composites with a pre-existing void. The results show that the pre-existing void collapses always perpendicular to the direction of the shock loading, regardless of whether the shock direction starts from the crystalline phase or the amorphous phase. The Cu/Cu₆₄Zr₃₆ composites are more prone to spallation failure when the shock starts from the Cu crystalline phase. The changes of dislocation density and shear transformation zone (STZ) activation are closely related to the magnitude and direction of shock velocity. When the shock velocity reaches 2.0 km/s, dislocations in the crystalline phase disappear, dislocation density is close to zero and STZs activate throughout the entire amorphous phase. In addition, regardless of the shock velocity and direction, no shear bands are generated in the Cu/Cu₆₄Zr₃₆ composites under shock loading, which is significantly different from the case of tensile loading.