Mechanical responses and deformation mechanisms of nanoporous glassy alloy under multiaxial loading: a molecular dynamics study

Nanoporous glassy alloys (NPGAs) have garnered significant interest due to their exceptional and tunable properties, yet their mechanical behavior under multiaxial loading remains poorly understood, hindering their practical applications. Here, we employ molecular dynamics simulations to investigate the mechanical properties, deformation mechanisms, and failure behaviors of a representative Cu₅₀Zr₅₀ NPGA under multiaxial loading. Our results reveal that the modulus of the NPGA increases markedly under multiaxial tension, while the ultimate tensile strength shows only a minor decline. Notably, the modulus strengthening effect in NPGAs is far more pronounced than that in traditional nanoporous gold (NPG), whereas the strength softening effect is considerably weaker. Both uniaxial and multiaxial tension deformations are governed by the combination of solid network bending and stretching, with the yield strength–solid fraction relationship conforming to the Gibson–Ashby model. Atomic-level analysis shows that the network skeleton undergoes elongation, yielding, necking, and rupture along the loading directions, with uniaxial tension generating a single fracture surface perpendicular to the loading direction and multiaxial tension inducing multiple fracture surfaces aligned with their respective loading axes. Quantitative analysis of atomic shear strain indicates that localized deformation and enhanced plastic strain lead to reduced yield strain and tensile strength under multiaxial loading. These findings provide valuable theoretical insights for the application of NPGAs in complex load-bearing environments.