Plastic deformation of Ag/MgO interface system during tensile fracture: A molecular dynamics study

Abstract

Fracture experiments on layered metal-ceramic composites show that the plastic dissipation in the metal near the crack tip accounts for most of the macroscopic fracture toughness. In this work we studied the microscopic plastic deformation mechanisms of Ag/MgO interface systems using molecular dynamics (MD) method. As tensile strain increases, lattice dislocations nucleate at interface misfit dislocations and propagate in metal layer. The formation of immobile Hirth dislocations in Ag causes hardening. As the metal layer increases, the yield strength decreases and the hardening range is shortened. Large interface area increases the degree of inhomogeneity of dislocation motion and interface fracture behavior, leading to decreased interface yield strength.