Co-evolution of the atomic/nano scale structural heterogeneities and magnetic properties of Fe-Si-B-Cu metallic glass during relaxation with composition fluctuations

The metallic glass (MG) exhibits composition fluctuation or chemical heterogeneity during relaxation. However, the influence of this factor on the evolution of the intrinsic structural heterogeneity of MGs remains unclear. In this study, we systematically examined the co-evolution between atomic and nano-scale structural heterogeneities of Fe-Si-B-Cu MGs during relaxation. We discovered that, despite some degree of fluctuation in composition during the relaxation of Fe-Si-B-Cu MGs, it does not prevent the reduction of structural heterogeneities at the atomic/nano scale. The results demonstrate an overall increase in the number density and number of types of densely packed clusters with a high degree of local five-fold symmetry and a decrease in the number density and number of types of loosely packed clusters with a low degree of local five-fold symmetry. Furthermore, a certain degree of compositional fluctuation during relaxation of Fe-Si-B-Cu MGs facilitates the formation of uniformly distributed Fe-rich regions and Cu-rich regions.