The influence of periodic wavy interfaces on the mechanical properties of Cu/Ta nanomultilayers

A large number of experiments and molecular dynamics (MD) simulations demonstrate that the interface structure plays a critical role in the mechanical properties of metallic nanomultilayers. However, at present, the effect of interface morphology on the mechanical response and deformation mechanism of the metallic nanomultilayers is rarely studied, and the potential mechanism is still unclear. In this work, Cu/Ta nanomultilayers were selected as the research objects. Through MD simulations, the tensile flow stress, strain incompatibility, and deformation mechanism of the normal sample with flat interfaces and the samples with periodic wavy interfaces were systematically studied. The simulation results show that the periodic wavy interfaces not only effectively improve the flow stress of the Cu/Ta nanomultilayers but also greatly suppress the strain incompatibility of the Cu/Ta nanomultilayers. Moreover, with the increase of the surface area of the wavy interfaces per unit volume, not only multiple dislocation slip systems were activated earlier, but also a new deformation mechanism was generated in the Cu/Ta nanomultilayers. The findings in this work provide a new insight for the strength-toughening design of the metallic nanomultilayers.