Atomic-scale mechanisms of tension–compression asymmetry in a metallic glass

Materials exhibit a tension–compression asymmetry in terms of plasticity. This phenomenon is usually interpreted by continuum mechanics, which neglects the stress-induced structure change. Here we investigated the structure change of a metallic glass of Zr46.5Cu45Al7Ti1.5 (in at.%) under both tensile and compressive stresses by in situ loading and high-energy X-ray scattering. A relationship between the stress-induced structure change and the extraordinary tension–compression asymmetry of plasticity in the metallic glass is presented. Another interesting phenomenon is that the metallic glass also exhibits tension–compression asymmetry in terms of crystallization. The influence of the stress-induced structure change on the crystallization behavior of metallic glasses is discussed. The results obtained here reveal the structure evolution of a metallic glass under both tensile and compressive stresses, and might provide a new perspective on the tension–compression asymmetry in the structure of amorphous solids.