On the characteristic length scales associated with plastic deformation in metallic glasses

Abstract

Atomistic simulations revealed that the spatial correlations of plastic displacements in three metallic glasses, FeP, MgAl, and CuZr, follow an exponential law with a characteristic length scale ℓc that governs Poisson’s ratio ν⁠, shear band thickness tSB⁠, and fracture mode in these materials. Among the three glasses, FeP exhibits smallest ℓc⁠, thinnest tSB⁠, lowest ν⁠, and brittle fracture; CuZr exhibits largest ℓc⁠, thickest tSB⁠, highest ν⁠, and ductile fracture, while properties of MgAl lie in between those of FeP and CuZr. These findings corroborate well with existing experimental observations and suggest ℓc as a fundamental measure of the shear transformation zone size in metallic glasses.