Dislocation interaction and fracture of Cu/Ta bilayer interfaces

In this article, the mechanical properties and dynamic responses of Cu/Ta nanofilms with a hole defect under tension process were investigated using molecular dynamics simulation. The effects of temperature, the diameter of hole defect, strain rate and growing orientation were evaluated in terms of stress-strain relationship, dislocation mechanism, structural phase transformations, interface response, and local stress concentration. The results show that the phase transformations from fcc into HCP structures, and 〈112〉, 〈110〉 dislocations were found in Cu sections. The tensile strength reduced with the increasing temperature and increasing the diameter of the hole defect. In contrast, the tensile strength increased under the strain rate increased. The greater stress concentration factor at the higher temperature, however, the smaller stress concentration factor with the larger diameter of hole defect. The void growth expanded stronger at smaller hole defect. Between the nanofilms with different growing orientations, the Cu [100]/Ta [111] nanofilms exhibited the most excellent mechanical characteristics.