Diffusion-mediated chemical concentration variation and void evolution in ion-irradiated NiCoFeCr high-entropy alloy

Zhe Fan, Weicheng Zhong, Ke Jin, Hongbin Bei, Yuri N. Osetsky, Yanwen Zhang

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

High-entropy alloys (HEAs) are proposed as potential structural materials for advanced nuclear systems, but little is known about the response of matrix chemistry in HEAs upon irradiation. Here, we reveal a substantial change of matrix chemical concentration as a function of irradiation damage (depth) in equiatomic NiCoFeCr HEA irradiated by 3 MeV Ni ions. After ion irradiation, the matrix contains more Fe/Cr in depth shallower than ~900–1000 nm but more Ni/Co from ~900–1000 nm to the end of the ion-damaged region due to the preferential diffusion of vacancies through Fe/Cr. Preferential diffusion also facilitates migration of vacancies from high radiation damage region to low radiation damage region, leading to no void formation below ~900–1000 nm and void formation around the end of the ion-damaged region at a fluence of 5 × 1016 cm−2 (~123 dpa, displacements per atom, peak dose under full cascade mode). As voids grow significantly at an increased fluence (8 × 1016 cm−2, 196 dpa), the matrix concentration does not change dramatically due to new voids formed below ~900–1000 nm. [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)298-310
Number of pages13
JournalJournal of Materials Research
Volume36
Issue number1
DOIs
StatePublished - Jan 2021
Externally publishedYes

Keywords

  • chemical concentration
  • defect migration
  • diffusion
  • high-entropy alloys
  • void swelling

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