Impact of shadow glass transition on crystallization in metallic glass

The stability of glass against crystallization is of importance in practical applications and theoretical understanding of the nature of glass materials. Annealing has complicated influences on glass stability. It induces either delayed or early crystallization, depending on detailed protocols and specific materials. By interrogating the thermal behaviors of twelve metallic glasses(MGs), we find that enhanced stability is correlated to another process: the so-called shadow glass transition and its evolution. Delayed crystallization can be observed when the shadow glass transition is shifted to cross the temperature of crystallization. Concurrently, the shadow glass transition evolves to an enthalpy overshoot. Molecular dynamics simulations support these findings and suggest that the suppressed string-like motion, relating to the shadow glass transition and the enthalpy overshoot, is likely the origin of the postponed nucleation ordering and enhanced glass stability.