Mechanical properties, failure mechanisms, and scaling laws of bicontinuous nanoporous metallic glasses

Molecular dynamics simulations are employed to study the mechanical properties of nanoporous CuxZr1-x metallic glasses (MGs) with five different compositions, x = 0.28 , 0.36, 0.50, 0.64, and 0.72, and poros-ity in the range 0.1 < phi < 0.7. Results from tensile loading simulations indicate a strong dependence of Young's modulus, E, and Ultimate Tensile Strength (UTS) on porosity and composition. By increasing the porosity from phi = 0.1 to phi = 0.7, the topology of the nanoporous MG shifts from closed cell to open-cell bicontinuous. The change in nanoporous topology enables a brittle-to-ductile transition in deformation and failure mechanisms from a single critical shear band to necking and rupture of ligaments. Genetic Programming (GP) is employed to find scaling laws for E and UTS as a function of porosity and com-position. A comparison of the GP-derived scaling laws against existing relationships shows that the GP method is able to uncover expressions that can predict accurately both the values of E and UTS in the whole range of porosity and compositions considered. (C) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

Molecular dynamics simulations are used to investigate the mechanical properties of nanoporous CuxZr1-x metallic glasses. The study reveals a strong correlation between Young's modulus, Ultimate Tensile Strength (UTS), and porosity/composition. Increasing porosity leads to a change in nanoporous topology and a transition from brittle to ductile deformation and failure mechanisms. Genetic Programming (GP) is employed to establish scaling laws for E and UTS as a function of porosity and composition, accurately predicting their values in the entire range considered.