Relaxation-to-rejuvenation transition of a Ce-based metallic glass by quenching/cryogenic treatment performed at sub-Tg

Abstract

Ce69Al10Cu20Co1 metallic glass was fully annealed to its metastable equilibrium supercooled liquid (MESL) state at a temperature below the calorimetric glass transition, i.e., sub-Tg, and quenching/cryogenic combined treatment (Quenching + CT) was subsequently manipulated in liquid nitrogen. The evolution of glass transition, specific heat capacity (Cp) and enthalpy change (ΔH) were investigated by differential scanning calorimetry (DSC). Rejuvenation phenomenon on the perspective of energy level was found compared with the relaxed state of the sample. The evolution of the structural states, including the free volume, internal stress and atomic clusters, that caused by the quenching process and subsequent cryogenic treatment is discussed and acted as the physical interpretation to the relaxation-to-rejuvenation transition.