The new research on intrinsic correlation between the fraction of liquid-like zones and the beta-relaxation in high-entropy metallic glasses

Researchers Y. J. Duan, E. Pineda and D. Crespo, from the Group of Materials Characterization of the UPC, have made new progress to understand the mechanical properties of high-entropy metallic glasses. The work clarifies the correlation between the fraction of liquid-like zones, i.e. the fraction of atoms that can easily rearrange under the effect of external forces, and the secondary or β relaxation observed in these materials. Besides, the work reveals the high-entropy effect on the supercooled liquid dynamics of the metallic melt.

Owing to the disordered atomic structure, metallic glasses (MGs) show unique properties. Besides, high-entropy alloys (HEAs), containing equimolar concentrations of each component, have been developed recently. Benefitting from the high configurational entropy, large lattice distortion, sluggish diffusion and the cocktail effect, HEAs exhibit distinctive physical and mechanical properties. With the aim of blending the properties of MGs and HEAs, high-entropy metallic glasses (HEMGs) have been developed. However, the existence of specific properties of HEMGs as compared to other families of MGs, especially the presence of a high entropy - sluggish diffusion effect and its effects on the glass-to-liquid transition and the aging/rejuvenation processes, which are essential to control the glassy configuration and adjust the materials properties, have not been clearly demonstrated

We report in the manuscript “Intrinsic Correlation between the Fraction of Liquidlike Zones and the β-Relaxation in High-Entropy Metallic Glasses” the evolution of stress relaxation of high-entropy metallic glasses with distinc β-relaxation behavior. The fraction of liquid-like zones, determined at each temperature by the intensity of stress decay, is shown to be directly related to both the aging process and the spectrum of relaxation modes obtained by mechanical spectroscopy. The results shed light on the intrinsic correlation between the static and dynamic mechanical response in high-entropy and conventional metallic glasses, pointing towards a sluggish diffusion high-entropy effect in the liquid dynamics.

Reference:

Y. J. Duan, L. T. Zhang, J. C. Qiao, Yun-Jiang Wang, Y. Yang, T. Wada, H. Kato, J. M. Pelletier, E. Pineda, and D. Crespo, Intrinsic Correlation between the Fraction of Liquidlike Zones and the β-Relaxation in High-Entropy Metallic Glasses, Phys. Rev. Lett. 129, 175501 (2022)

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