Decoupling between calorimetric and dynamical glass transitions in high-entropy metallic glasses.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34158476.
- Also identified by DOI 10.1038/s41467-021-24093-w and PMC identifier 8219663.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Glass transition is one of the unresolved critical issues in solid-state physics and materials science, during which a viscous liquid is frozen into a solid or structurally arrested state. On account of the uniform arrested mechanism, the calorimetric glass transition temperature (T<sub>g</sub>) always follows the same trend as the dynamical glass transition (or α-relaxation) temperature (T<sub>α</sub>) determined by dynamic mechanical analysis (DMA). Here, we explored the correlations between the calorimetric and dynamical glass transitions of three prototypical high-entropy metallic glasses (HEMGs) systems. We found that the HEMGs present a depressed dynamical glass transition phenomenon, i.e., HEMGs with moderate calorimetric T<sub>g</sub> represent the highest T<sub>α</sub> and the maximum activation energy of α-relaxation. These decoupled glass transitions from thermal and mechanical measurements reveal the effect of high configurational entropy on the structure and dynamics of supercooled liquids and metallic glasses, which are associated with sluggish diffusion and decreased dynamic and spatial heterogeneities from high mixing entropy. The results have important implications in understanding the entropy effect on the structure and properties of metallic glasses for designing new materials with plenteous physical and mechanical performances.