Computer simulation study of the atomistic mechanism of deformation and fracture initiation in thin fcc metal films

A molecular dynamics computer simulation was performed using a potential of embedded atom method (EAM) of copper so as to study the atomistic mechanism of plastic deformation in thin metal films. When a thin film of Cu crystal is elongated by more than 8%, small islands of surplus atoms start to nucleate between (111) planes. The formation of new (111) islands occurs by the movement of atoms along the 〈111〉 direction from two successive (111) planes. Multiplication of these (111) planes serves as the mechanism of elongation, releasing the accumulated elastic stress. Vacancies and small clusters, thereof, are left behind at the positions from which atoms have migrated and also at the part of newly nucleated (111) planes in which atoms were not filled completely. Stacking fault tetrahedra (sft) are nucleated directly in the deformed region as a result of movement of atoms along 〈111〉 on the tetrahedral (111) cap.