Effect of pore design on the mechanical properties of nanoporous high-entropy alloys

Abstract

To reveal the dependence of mechanical properties upon the pore design, we perform molecular dynamics simulations to investigate the tensile responses of nanoporous Cantor high-entropy alloys (HEAs), considering the effects of pore size, pore distribution, pore shape, pore spacing, and pore density. Decreasing the pore spacing promotes the transition of fracture mechanism from shear banding to necking. Depending on the pore distribution in the heterostructures, the deformation induced by multiple shear bands and the transition of FCC phase to HCP phase are observed, which is conducive to the homogeneous plastic flow and the enhanced ductility. Pore shape dictates the stress distribution and accumulation closely related to failure mechanisms and mechanical properties of nanoporous HEAs, such as the bending-dominated signature of circle pore and the stretching-dominated signature of ellipse pore producing enhanced modulus and strength. With constrained geometries, “smaller is stronger” is observed in the size effect of neck width. The scaling laws of modulus and strength versus relative density and neck width are derived and developed. The investigation further clarifies the structure–property relationship of nanoporous HEAs and highlights a new strategy for enhanced plasticity by the pore design.Subject Areas: material science, computational material.