Dislocation emission and crack propagation during thin film buckling on substrate

Abstract

The buckling of a gold thin film deposited on a rigid substrate has been numerically investigated by means of static molecular dynamics simulations. Three different regimes of deformation have been identified depending on the values of the adhesion energy of the film on its substrate (Γint). For low adhesion energy, the buckling and gliding through dislocation emission into the interface have been observed. For intermediate values of Γint, the dissociation of the interfacial dislocations into the film leads to the formation of a Lomer–Cottrell lock that stops the buckle extension, promoting thus the propagation of a crack accompanied by the emission of dislocations. It results in the formation of a twin. For large values of Γint, the kinking of the interfacial crack has been evidenced along with dislocation nucleation at its tip leading to twins again. Finally, the different evolutions of the film have been summarized in a “behavior” diagram displayed in the plane of applied strain and adhesion energy variables.