Investigation on the thermodynamic stability of nanocrystalline W-based alloys: A combined theoretical and experimental approach

Francesco Torre, Claudio Mingazzini, Daniele Mirabile Gattia, Teodor Huminiuc, Antonio Rinaldi, Tomas Polcar, Francesco Delogu, Antonio Mario Locci*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Abstract

The stability of nanostructured metal alloys is currently being extensively investigated, and several mathematical models have been developed to describe the thermodynamics of these systems. However, model capability in terms of thermal stability predictions strongly relies on grain boundary-related parameters that are difficult to measure or estimate accurately. To overcome this limitation, a novel theoretical approach is proposed and adopted in this work to identify W-based nanocrystalline alloys which are potentially able to show thermodynamic stability. A comparison between model outcomes and experimental findings is reported for two selected alloys, namely W-Ag and W-Al. Experimental results clearly highlight that W-Ag mixtures retain a segregated structure on relatively coarse length scales even after prolonged mechanical treatments. Moreover, annealing at moderate temperatures readily induces demixing of the constituent elements. In contrast, homogeneous nanostructured W-Al solid solutions are obtained by ball milling of elemental powders. These alloys show enhanced thermal stability with respect to pure W even at high homologous temperatures. Experimental evidences agree with model predictions for both the investigated systems.

Original languageEnglish
Article number7179
Number of pages18
JournalMaterials
Volume14
Issue number23
DOIs
Publication statusPublished - 25 Nov 2021

Keywords

  • Nanocrystalline alloys
  • Thermal stability
  • Thermodynamics
  • UKRI
  • EPSRC
  • EP/R041768/1

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