Atomistic understanding of creep and relaxation mechanisms of Cu64Zr36 metallic glass at different temperatures and stress levels

WP Wu and D Sopu and X Yuan and O Adjaoud and KK Song and J Eckert, JOURNAL OF NON-CRYSTALLINE SOLIDS, 559, 120676 (2021).

DOI: 10.1016/j.jnoncrysol.2021.120676

In this paper, the tensile creep behavior of Cu64Zr36 metallic glass (MG) is investigated by molecular dynamics simulations. The effects of stress and temperature on the evolution of activated states during nanoscale creep tests are discussed, the creep failure time is predicted by linear regression analysis and three creep mechanisms are found. The creep mechanisms at the low stress and high temperature regime is dominated by thermally activated atomic diffusional creep; the low temperature and low stress regime is dominated by anelastic deformation and homogeneous activation of elastic events, while the low temperature and high stress regime is governed by local inhomogeneous shear deformation through shear transformation zones (STZs) percolation and embryonic shear band formation. These mechanisms help to further understand the creep behavior and derive an atomistic description of the relationship between the creep behavior and the three mechanisms of mechanical relaxations in MGs: atomic diffusion via cooperative atomic motion or a relaxation, stress-induced STZs activation such as slow beta relaxation and anelastic deformation (fast beta' relaxation), respectively.

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