High strain-rate effect on microstructure evolution and plasticity of aluminum 5052 alloy nano-multilayer: A molecular dynamics study

Abstract

Effects of strain rates on mechanical behaviors of nano-multilayered aluminum 5052 alloys are explored via molecular dynamics simulations. Yield strength and ultimate tensile strength increase with an increase in strain rates. The increase of the yield stress with the strain rate is caused by the delay in the onset of dislocation propagation. In addition, the strain rate sensitivity and the yield stress activation volume significantly depend on strain rate. Under tensile loading, the pristine face-centered cubic structure of the alloy successively transforms to a hexagonal close-packed structure through the intermediate body-centered cubic structure during plastic deformation processes, regardless of strain rates. Dislocation density and volume fraction of phase significantly depend on strain rate. In addition, discussions on the formation, movement, and interaction of dislocations under low and high strain rates are presented.