On the strain rate sensitivity of mechanical properties of nanoporous gold: Temperature effect

Abstract

Nanoporous metals show promising potential applications in catalysis and micro/nano devices, and clarifying the mechanical properties of nanoporous metals under various conditions is critical to utilize the materials in functionalized applications. In this work, the tensile mechanical responses of nanoporous gold are investigated via molecular dynamics simulations, emphasizing the effects of strain rate and temperature. Results show that the mechanical properties, including Young’s modulus and ultimate strength, are positively correlated with the applied strain rate and decrease in linearity with increasing temperature. It is interesting to note that there is a presence of a critical strain rate of 109s-1, at which the strain-rate sensitivity and temperature sensitivity change significantly. The temperature sensitivity and modulus are insensitive to the applied strain rate below 109s-1 while the stain-rate sensitivity is enhanced with the strain rate beyond 109s-1. The strain-rate sensitivity is sensitive to temperature and increases significantly with increasing temperature. Temperature and strain rate also affect the elastic-plastic deformation behaviors of the material. The findings further deepen the atomistic understanding of the mechanical properties of nanoporous metals and guide for the strain-rate selection (not more than 109s-1) in molecular dynamics simulations.