Abstract
Recombination of Frenkel defects is an important process that contributes to the performance of materials under irradiation. In this work, the recombination mechanisms of Frenkel defects in face-centered cubic Ni and Ni‒containing solid‒solution alloys are investigated based on interatomic potentials and ab initio calculations. It is found that, in pure Ni, the spontaneous recombination volume for a [100] dumbbell interstitial is 18Ω and 34Ω (Ω is the atomic volume) with the empirical potential and ab initio method respectively. Addition of Fe atoms increases the spontaneous recombination volume of Frenkel defects significantly. For those stable Frenkel defects that cannot recombine, a stronger attractive force between the interstitial and the vacancy is found in concentrated Ni‒Fe alloys compared to in pure Ni, which provides the driving force for enhanced recombination. The distribution of life-time for Frenkel defects at finite temperature suggests that recombination in Ni‒Fe alloys is delayed due to the sluggish diffusion of interstitials. Finally, recombination in Ni‒Fe‒Cr alloys is studied by substituting a portion of Fe in Ni‒Fe with Cr. A remarkable increase in recombination probability is observed in this case because of the presence of less stable Cr‒containing than Fe‒containing dumbbell interstitials and lower migration barriers of vacancies. This work reveals that higher defect recombination probability in concentrated alloys is responsible for the experimentally observed enhanced irradiation resistance.
Original language | English |
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Pages (from-to) | 184-194 |
Number of pages | 11 |
Journal | Acta Materialia |
Volume | 173 |
DOIs | |
State | Published - Jul 2019 |
Funding
This work was supported as part of the Energy Dissipation to Defect Evolution (EDDE) , an Energy Frontier Research Center funded by the U.S. Department of Energy , Office of Science , Basic Energy Sciences under contract number DE-AC05-00OR22725 . Calculations during the revision stage was supported by City University of Hong Kong through project No. 9610425 .
Funders | Funder number |
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U.S. Department of Energy | |
Office of Science | |
Basic Energy Sciences | DE-AC05-00OR22725 |
City University of Hong Kong | 9610425 |
Keywords
- Atomistic simulations
- Concentrated solid-solution alloys
- Frenkel defect recombination
- Irradiation effects
- Metallic alloys