Abstract
Defect evolution under irradiation is investigated in a set of single-phase concentrated solid solution alloys (SP-CSAs) containing Ni with Co, Fe and/or Cr. We show that atomic segregation of Ni takes place already at very early stages of radiation damage in the 2–4 element SP-CSAs containing Fe or Cr, well below 1 dpa. We arrive at this conclusion by following the evolution of positron annihilation signals as a function of irradiation dose in single crystal samples, complemented by molecular dynamics simulations in the same model systems for high entropy alloys (HEAs). This manifestation of short-range order calls attention to composition fluctuations at the atomic level in irradiated HEAs. Ion irradiation may induce short-range order in certain alloys due to chemically biased elemental diffusion. The work highlights the necessity of updating the assumption of a totally random arrangement in the irradiated alloys, even though the alloys before irradiation have random arrangements of different chemical elements.
| Original language | English |
|---|---|
| Pages (from-to) | 44-51 |
| Journal | Acta Materialia |
| Volume | 196 |
| DOIs | |
| Publication status | Published - 1 Sept 2020 |
| MoE publication type | A1 Journal article-refereed |
Funding
The work performed by the researchers at Aalto University was supported by the Academy of Finland grants 285809, 293932 and 319178. The work performed by the researchers in USA 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. Ion irradiations were performed at the Ion Beam Materials Laboratory (IBML), located on the campus of the University of Tennessee, Knoxville. The University of Helsinki part of this work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014?2018 under grant agreement No 633053.