Dynamic Mechanical Behaviour In Ce-based Metallic Glasses

Metallic glass is a kind of matter in metastable state, will spontaneously relax toequilibrium state. Currently, the research of relaxation in metallic glasses mainlyfocused on two kinds of relaxation: α relaxation and slow β relaxation. Among them,slow β relaxation in lots of metallic glasses show as the shoulder in temperature sweepor excess wing in frequency sweep, only in few metallic glasses show as the obviousslow β relaxation peak. The presentation of slow β relaxation is related to the mixingenthalpy in atomic pairs. Ce based metallic glass provides a big advantage to investigaterelaxation for it exhibits relatively large supercooled liquid region and quite low glasstransition temperature. We measured the temperature-modulus sweep andfrequency-modulus sweep of Ce-Al-Cu/Ce-Ga-Cu metallic glasses by dynamicmechanical analysis in this text, and the strength of slow β relaxation was analyzedcombined with the mixing enthalpy between atoms. Found that the mixing enthalpybetween atoms isn’t simply heighten or weaken the strength of slow β relaxation. Therelation between them is quite complicated.Besides, the α relaxation in supercooled liquids region of Ce70Ga8.5Cu18.5Ni3metallic glass and the stress relaxation after12days and160days annealing at roomtemperature in sub-Tgarea were measured. Found that the relaxation mechanismchanged at Tgand the annealing at room temperature got an obvious influence on thestress relaxation in sub-Tgarea and the activation energy of it. Moreover, the stressrelaxation in sub-Tgarea is closely related to slow β relaxation.