Correlation between elastic structural behavior and yield strength of metallic glasses

Tremendous research effort has been put into the study of plastic deformation mechanisms of metallic glasses (MGs) in an attempt to elucidate the origin of their high fracture strength. Little attention has, however, been paid to the elastic deformation of MGs. In this paper, a series of MGs with different yield strengths are studied, with a focus on the fine structural evolution (at the atomic level) during elastic deformation. Our results reveal that an atomic reorientation happens in the first nearest-neighbor shell due to elastic deformation. This reorientation subsequently leads to a drop in the local stress, which further results in a cooperative shift of surrounding atoms to counterbalance this change in local stress level. A concordant region is formed as a result. The relation between this concordant region and the yield strength is thoroughly discussed in terms of its size and the stress level in this region. It is proposed that this concordant region could be the missing part that bridges the macroscopic yield strength and the microscopic atomic structure.