Eshelby-inclusion characteristics of shear rearrangements in amorphous solids

Shear transformations (STs), as the fundamental events of plastic deformation of amorphous solids, remain a great deal of uncertainty regarding their basic characteristics. Here we propose an effective method for extracting these basic characteristics by means of fitting the spatial correlation of strain fields to the solutions of Eshelby's inclusion theory. Our method identifies individual STs from plastic events and eliminates the influence of local fluctuations, which greatly improves the effectiveness of the fitting results. Using this method, the Eshelby characteristics of STs and the relationship between STs and atomic structure are investigated in the atomistic simulations of a Cu_{50}Zr_{50} model glass. The broad distributions of Eshelby characteristics confirm the heterogeneous and anisotropic nature of STs. The shape of STs closely approximates a sphere, with the inclusion radius approaching 1.5 times the atomic size. Except for the component along the macroscopic loading direction, the other eigenstrain components generally follow a Gaussian distribution. The shear deformation of STs is much smaller than previously believed. The volumetric deformation of STs can be either dilatational or compressive, with a slight preference for dilatation. The further softening induced by STs is due to the fact that the promoting effect of local dilatation overweighs the suppressive effect of structural ordering. Our method can extract key information of STs for establishing a constitutive model that bridges the gap between microscopic atomic rearrangements and macroscopic plastic response.