Mixed-mode fracture toughness testing of a Cu/Ag bimetallic interface via atomistic simulations

摘要

This work presents the evaluation of mixed-mode fracture toughness for an interface crack using molecular dynamics simulations. A Cu/Ag bimetallic structure with an interface crack was configured, where the atomic interactions were characterized based on the embedded-atom method potential. A bimaterial K-field of linear elastic fracture mechanics was employed as a remote loading for the mixed-mode failure. The traction ratio of the shear to normal component in front of a crack tip was defined as the mode mixity. The critical value of the J-integral for the onset of crack growth along the interface was measured as the interfacial fracture toughness; the value was also compared to the critical energy release rate and the Griffith fracture toughness. The interfacial fracture toughness of a Cu/Ag bimaterial was found to exhibit significant dependence on mode mixity for an interface crack, which resulted from various types of atomic-scale deformation at the interface.