Tensile mechanical properties of nano-twinned copper containing silver inclusions

Abstract

Nano-twins have been proven to be an efficient way to optimize the mechanical performance, e.g., strength and ductility, of metal materials. In this paper, molecular dynamics method is employed to simulate the uni-axial tension process of nano-twinned copper with silver inclusions, focusing on the influence of structural parameters of inclusions on the tensile mechanical properties, especially the ultimate strength and flow stress. It is shown from the obtained results that decreasing the inclusion volume fraction or increasing the inclusion size will lead to the increase of the ultimate strength of nano-twinned materials. Moreover, the strength shows an approximately linear dependence on the inclusion shape ratio for a fixed volume. Besides, the strength of nano-twinned materials containing inclusions follows the conventional Hall-Petch relationship as the twin spacing varies. When the twin thickness is 10 nm, due to the increasing blocking effect to dislocation gliding, the average flow stress of nano-twinned materials increases with increasing the inclusion volume fraction. These findings may shed light on the understanding of both mechanical property and potential application of new functional composite materials based on nano-twinned metals considering the effect of inclusions.