On the kinetics of structural evolution in metallic glasses

The classic phenomenological models fail to describe the physical landscape of creep deformation for amorphous solids. In this paper, creep behavior of typical metallic glasses with chemical compositions La62Al14Ag2.34Ni10.83Co10.83, Pd20Pt20Cu20Ni20P20 and Cu46Zr39Hf8Al7 were studied. Instead, we attempt to use a modified hierarchically correlated model informed by physics to realize the creep behaviors of metallic glasses. The anelastic deformation of creep is categorized into two distinct components, i.e., the highly correlated deformation unit sensitive to annealing and the low correlated unit associated with diffusion relaxation. The correlated component diminishes with structural aging. The validity of the model is verified by these findings, and the derived parameters provide insights into the structural and kinetic characteristics of metallic glasses. Decreased characteristic times and contrasting correlation factors indicate homogeneous structure and lower energy states. Moreover, a qualitative evaluation of the relative strengths of the dual deformation mechanisms during creep enables the characterization of beta relaxation forms, shedding light on the intrinsic attributes of different types of metallic glasses. This methodology additionally facilitates the detection of structural aging and rejuvenation phenomena.