On the Fragility of Bulk Metallic Glass Forming Liquids
In contrast to pure metals and most non-glass forming alloys, metallic glass-formers are moderately strong liquids in terms of fragility. The notion of fragility of an undercooling liquid reflects the sensitivity of the viscosity of the liquid to temperature changes and describes the degree of depar...
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MDPI AG
2017-09-01
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| Series: | Entropy |
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| Online Access: | https://www.mdpi.com/1099-4300/19/9/483 |
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| author | Isabella Gallino |
| author_facet | Isabella Gallino |
| author_sort | Isabella Gallino |
| collection | DOAJ |
| description | In contrast to pure metals and most non-glass forming alloys, metallic glass-formers are moderately strong liquids in terms of fragility. The notion of fragility of an undercooling liquid reflects the sensitivity of the viscosity of the liquid to temperature changes and describes the degree of departure of the liquid kinetics from the Arrhenius equation. In general, the fragility of metallic glass-formers increases with the complexity of the alloy with differences between the alloy families, e.g., Pd-based alloys being more fragile than Zr-based alloys, which are more fragile than Mg-based alloys. Here, experimental data are assessed for 15 bulk metallic glasses-formers including the novel and technologically important systems based on Ni-Cr-Nb-P-B, Fe-Mo-Ni-Cr-P-C-B, and Au-Ag-Pd-Cu-Si. The data for the equilibrium viscosity are analyzed using the Vogel–Fulcher–Tammann (VFT) equation, the Mauro–Yue–Ellison–Gupta–Allan (MYEGA) equation, and the Adam–Gibbs approach based on specific heat capacity data. An overall larger trend of the excess specific heat for the more fragile supercooled liquids is experimentally observed than for the stronger liquids. Moreover, the stronger the glass, the higher the free enthalpy barrier to cooperative rearrangements is, suggesting the same microscopic origin and rigorously connecting the kinetic and thermodynamic aspects of fragility. |
| first_indexed | 2024-04-11T12:32:36Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1099-4300 |
| language | English |
| last_indexed | 2024-04-11T12:32:36Z |
| publishDate | 2017-09-01 |
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| series | Entropy |
| spelling | doaj.art-b9361d5e5685493596b2eed413d063e22022-12-22T04:23:43ZengMDPI AGEntropy1099-43002017-09-0119948310.3390/e19090483e19090483On the Fragility of Bulk Metallic Glass Forming LiquidsIsabella Gallino0Department of Materials Science and Engineering, Saarland University, Campus C6.3, 66123 Saarbrücken, GermanyIn contrast to pure metals and most non-glass forming alloys, metallic glass-formers are moderately strong liquids in terms of fragility. The notion of fragility of an undercooling liquid reflects the sensitivity of the viscosity of the liquid to temperature changes and describes the degree of departure of the liquid kinetics from the Arrhenius equation. In general, the fragility of metallic glass-formers increases with the complexity of the alloy with differences between the alloy families, e.g., Pd-based alloys being more fragile than Zr-based alloys, which are more fragile than Mg-based alloys. Here, experimental data are assessed for 15 bulk metallic glasses-formers including the novel and technologically important systems based on Ni-Cr-Nb-P-B, Fe-Mo-Ni-Cr-P-C-B, and Au-Ag-Pd-Cu-Si. The data for the equilibrium viscosity are analyzed using the Vogel–Fulcher–Tammann (VFT) equation, the Mauro–Yue–Ellison–Gupta–Allan (MYEGA) equation, and the Adam–Gibbs approach based on specific heat capacity data. An overall larger trend of the excess specific heat for the more fragile supercooled liquids is experimentally observed than for the stronger liquids. Moreover, the stronger the glass, the higher the free enthalpy barrier to cooperative rearrangements is, suggesting the same microscopic origin and rigorously connecting the kinetic and thermodynamic aspects of fragility.https://www.mdpi.com/1099-4300/19/9/483bulk metallic glassesfragilityspecific heat capacityviscosityconfigurational entropyactivation energy |
| spellingShingle | Isabella Gallino On the Fragility of Bulk Metallic Glass Forming Liquids Entropy bulk metallic glasses fragility specific heat capacity viscosity configurational entropy activation energy |
| title | On the Fragility of Bulk Metallic Glass Forming Liquids |
| title_full | On the Fragility of Bulk Metallic Glass Forming Liquids |
| title_fullStr | On the Fragility of Bulk Metallic Glass Forming Liquids |
| title_full_unstemmed | On the Fragility of Bulk Metallic Glass Forming Liquids |
| title_short | On the Fragility of Bulk Metallic Glass Forming Liquids |
| title_sort | on the fragility of bulk metallic glass forming liquids |
| topic | bulk metallic glasses fragility specific heat capacity viscosity configurational entropy activation energy |
| url | https://www.mdpi.com/1099-4300/19/9/483 |
| work_keys_str_mv | AT isabellagallino onthefragilityofbulkmetallicglassformingliquids |