Resolving β relaxation and enhancing thermal stability of the medium-entropy metallic glass Zr₃₅Ti₃₀Be_27.5Fe_7.5 through modulating initial cooling temperature

Most conventional metallic glasses often exhibit an excess wing rather than clear resolving the β relaxation, making it challenging to fully understand this kinetic phenomenon. In this study, we investigated β relaxation in Zr₃₅Ti₃₀Be_27.5Fe_7.5 metallic glasses by varying the initial cooling temperature while maintaining constant cooling rates. The study results demonstrate that increasing the initial cooling temperature effectively resolve the β relaxation, which in turn significantly influences the glass transition and crystallization temperatures, enhancing the thermal stability of the metallic glass. Stress relaxation studies indicate that glasses quenched from higher melt temperatures exhibit a lower non-exponential parameter β_KWW, indicative of greater dynamic heterogeneity, along with a broader distribution of relaxation times in the as-quenched samples. This study suggests that higher initial cooling temperatures not only facilitate a clearer examination of β relaxation but also promote structural heterogeneity in metallic glasses, which is linked to the observed β relaxation and the improvement in thermal stability.