Atomistic investigation of interface-dominated deformation mechanisms in nanolayered Cu–Ag eutectic alloy

Nanolayered Cu–Ag eutectic alloy is a promising radiation protection material due to its favorable mechanical properties and resistance to radiation rays. These unique properties can be attributed to its high density of interfaces in the nanoscale: from phase interface between copper and silver layers to nanoscale grain boundaries dividing the multiple eutectic grains. However, to date, the coupling effects of phase interface and grain boundary within the nanolayered Cu–Ag eutectic alloy have not been well investigated. Therefore, we employ molecular dynamics (MD) simulations to elucidate the interface-dominated mechanical response and microstructural evolution of this eutectic material system under tensile loadings. In our simulations, the mechanical responses of nanolayered Cu–Ag eutectic alloy under tension have shown four different stages based on varied dislocation motion modes: linear elastic stage, yield stage I (confined layer slip), yield stage II (interface crossing), and plateau stage. Throughout all the stages, interfaces exhibit dominant influence on the deformation of the alloy. Particularly, the grain size and layer thickness characterized by grain boundary and phase interface activity have shown intricate impact on the strength of the alloy, which is due to the competitive relation between interface activity and dislocation motions. In addition, diverse grains perform differently in both interface shear and dislocation propagation, contributing to the plastic deformation for the model. Finally, this study reveals the link between mechanical behavior and microscopic interfaces of nanolayered Cu–Ag eutectic alloy and sheds light on the synthesis processes for the material.