Molecular dynamics study of fracture and plastic deformation of Cu/Cu64Zr36 crystalline/amorphous composites with a pre-existing void

In this paper, the fracture behavior and damage mechanism of Cu/Cu ₆₄Zr ₃₆ crystalline/amorphous composites with a pre-existing void are investigated by molecular dynamics (MD) simulation. The results show that the incorporated Cu crystalline phase improves the global plasticity by dislocation slip, effectively avoids catastrophic localization and hinders shear band propagation by controlling the volume ratio of the crystalline/amorphous composite. As the volume fraction of crystalline phase increases, the dislocation density increases, while the degree of strain localization decreases which is associated with homogeneous activation of shear transformation zones (STZs). Numerous dislocation movements and homogeneous STZ activation become the main reason for enhancing the global plasticity of the composites. In addition, the existence of voids changes the distribution of shear strain: the peak shear strain is distributed around the void, where it is most likely to activate dislocation movement and STZ percolation as well as embryonic shear band formation.