Possible origin of $\beta$-relaxation in amorphous metal alloys from atomic-mass differences of the constituents

Abstract

We employ an atomic-scale theory within the framework of nonaffine lattice dynamics to uncover the origin of the Johari-Goldstein (JG) $\beta$-relaxation in metallic glasses (MGs). Combining simulation and experimental data with our theoretical approach, we reveal that the large mass asymmetry between the elements in a La${}_{60}$Ni${}_{15}$Al${}_{25}$ MG leads to a clear separation in the respective relaxation time scales, giving strong evidence that JG relaxation is controlled by the lightest atomic species present. Moreover, we show that only qualitative features of the vibrational density of states determine the overall observed mechanical response of the glass, paving the way for a possible unified theory of secondary relaxations in glasses.

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Cited by in corpus (4)

• Predicting Complex Relaxation Processes in Metallic Glass
• Relaxation and vibrational properties in metal alloys and other disordered systems
• Johari-Goldstein heterogeneous dynamics in a model polymer
• Secondary relaxation in the terahertz range in 2-adamantanone from theory and experiments