Mechanics of nanoscale metallic multilayers: From atomic-scale to micro-scale

Layered composites of Cu/Nb with incoherent interfaces achieve very high strength levels. Interfaces play a crucial role in determining this strength by acting as barriers to slip. Atomistic models of Cu/Nb bilayers are used to explore the origins of this resistance. The models clearly show that dislocations near an interface experience an attraction toward the interface. This attraction is caused by shear of the interface induced by the stress field of the dislocation. More importantly, atomistic simulations also reveal that interfacial dislocations easily move in interfaces by both glide and climb. Integrating these findings into a micro-scale model, we develop a three-dimensional crystal elastic–plastic model to describe the mechanical behavior of nanoscale metallic multilayers.