Determinants of vacancy formation and migration in high-entropy alloys.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39752502.
- Also identified by DOI 10.1126/sciadv.adr4697 and PMC identifier 11698082.
- Licence recorded as CC BY-NC.
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Abstract
Vacancies are crucial for the radiation resistance, strength, and ductility of high-entropy alloys (HEAs). However, complex electronic interactions resulting from chemical disorder prohibit the quantification of vacancy formation energy (<i>E</i><sub>f</sub>) and migration barriers (<i>E</i><sub>b</sub>). Herein, we propose an electronic descriptor χ<i>S</i><sub>v</sub> (electronegativity χ and valence-electron number <i>S</i><sub>v</sub>) to quantify the bonding strength of constituents on the basis of the tight-binding model, which allows us to build analytical models to achieve the site-to-site quantification of <i>E</i><sub>f</sub> and <i>E</i><sub>b</sub>. The descriptor χ<i>S</i><sub>v</sub> reflects the d-band occupation, indicating the dominant role of the electronic interactions in the vacancy formation and migration of HEAs. As a size effect, local lattice distortion plays a more important role in vacancy migration than in vacancy formation. Our model establishes a universal physical picture of vacancy formation and migration, which helps to understand the radiation resistance and mechanical properties of HEAs, thereby accelerating the design of high-performance HEAs.