Bridging shear transformation zone to the atomic structure of amorphous solids

• An atomic structure-based STZ (SSTZ) of amorphous solids is proposed.
• The universal yielding criterion of amorphous alloys is rationalized on an atomic level.
• Shear dilation in amorphous alloys is provided with a structure basis.

To correlate the atomic structure and mechanical behavior of amorphous solids, bridging shear transformation zone (STZ) to the atomic structure is crucial. Referring to dislocation of crystals and according to the concept of shear transformation in amorphous solids, from a mean perspective, an atomic structure-based shear transformation zone (SSTZ) based on radial distribution function (RDF) where an average atom is surrounded by atoms of different shells, is proposed. The elementary deformation event of the disordered structure is considered as a mean atomic rearrangement, i.e., a concordant rearrangement process between the atom shells in the SSTZ. The SSTZ will introduce no necessary modification into the transition state theory-based flow equation of amorphous alloys and provide both the universal yielding criterion and the anelastic deformation of amorphous alloys with a structure basis in terms of the shift of the peak on RDF under loading. Besides, regarding with issues like shear dilation and Poisson ratio etc., profound understandings can be achieved for the clear structural characteristic of the SSTZ.