Strain rate dependence of mechanical properties for sub 100 nm-thick Au film using Electrostatically Actuated NAno Tensile testing device

We have clarified the strain-rate dependence of mechanical properties of Au thin films with thicknesses less than 100 nm. Stress-strain relations of Au films were examined by tensile tests using the Electrostatically Actuated NAno Tensile testing devices (EANATs). Young´s modulus showed a substantially smaller value of 30 GPa in average compared to bulk material, and it had no strain-rate dependence. However, the yield stress depended on the strain rate. In particular, the yield stresses clearly decreased with decreasing strain rate in the range lower than 0.01 s^-1. TEM observation suggests that the differences were caused by the small grain size.