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

C Liu and SY Yuan and J Im and FPJ de Barros and SF Masri and PS Branicio, ACTA MATERIALIA, 239, 118255 (2022).

DOI: 10.1016/j.actamat.2022.118255

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.

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