Extra Phase Dynamics Hidden under Dynamics Relaxation Spectra of Amorphous Alloys

Dynamic relaxation is critically important in amorphous alloys and significantly affects the mechanical and glass transition behaviors. Nevertheless, the understanding of relaxation dynamics remains incomplete, particularly regarding how extra phase formation influences relaxation behaviors. Dynamic mechanical and electron microscopic analyses reveal the emergence of extra multiple amorphous phases in the model Cr_20.7Fe_22.6Co_22.6Ni_22.8Zr_11.3 amorphous alloy during the relaxation process. Contrary to typical single-phase amorphous systems, this amorphous alloy exhibits a premature decrease in the storage modulus from the shadow glass transition temperature instead of the conventional glass transition temperature. Furthermore, dynamics heterogeneity, characterized by the stretched exponent β_KWW, presents a potential correlation with the formation and percolation of extra phases: a decline in β_KWW coincides with the onset of extra phase formation, while an increase in β_KWW accompanies the percolation of these phases. These findings call for the integration of extra multiple phase formation and percolation into future models of relaxation dynamics.