Strain rate effects on tensile and compression behavior of nano-crystalline nanoporous gold: A molecular dynamic study

Abstract

In this study, strain rate effects on the tensile and compressive properties of nano-crystalline nanoporous gold (nc-NPAu) are investigated by performing molecular dynamics simulations. For this purpose, atomistic models of nc-NPAu structures with three different grain sizes are generated through a novel modeling technique based on the Voronoi tessellation method. Additionally, an adaptive common neighbor analysis (aCNA) is carried out to examine the evolution of the crystal structure. In this way, the deformation mechanisms of nc-NPAu atomistic models are thoroughly investigated. The findings point out that mechanical properties of nc-NPAu specimens such as toughness, ultimate and yield strengths grow at increasing strain rates for both tensile and compressive loadings while their elastic moduli exhibit less significant variations at different strain rates. Furthermore, the study also shows that in addition to dislocation motion, several other deformation mechanisms including grain rotation, grain boundary sliding and grain travelling are observed to be effective for nc-NPAu.