Abstract
The growth of advanced energy technologies for power generation is enabled by the design, development, and integration of structural materials that can withstand extreme environments, such as high temperatures, radiation damage, and corrosion. High-entropy alloys (HEAs) are a class of structural materials in which suitable chemical elements in four or more numbers are mixed to typically produce single-phase concentrated solid solution alloys (CSAs). Many of these alloys exhibit good radiation tolerance like limited void swelling and hardening up to relatively medium radiation doses (tens of displacements per atom (dpa)); however, at higher radiation damage levels (>50 dpa), some HEAs suffer from considerable void swelling limiting their near-term acceptance for advanced nuclear reactor concepts. In this study, we developed a HEA containing a high density of Cu-rich nanoprecipitates distributed in the HEA matrix. The Cu-added HEA, NiCoFeCrCu0.12, shows excellent void swelling resistance and negligible radiation-induced hardening upon irradiation up to high radiation doses (i.e., higher than 100 dpa). The void swelling resistance of the alloy is measured to be significantly better than NiCoFeCr CSA and austenitic stainless steels. Density functional theory simulations predict lower vacancy and interstitial formation energies at the coherent interfaces between Cu-rich nanoprecipitates and the HEA matrix. The alloy maintained a high sink strength achieved via nanoprecipitates and the coherent interface with the matrix at a high radiation dose (∼50 dpa). From our experiments and simulations, the effective recombination of radiation-produced vacancies and interstitials at the coherent interfaces of the nanoprecipitates is suggested to be the critical mechanism responsible for the radiation tolerance of the alloy. The materials design strategy based on incorporating a high density of interfaces can be applied to high-entropy alloy systems to improve their radiation tolerance.
| Original language | English |
|---|---|
| Pages (from-to) | 3912-3924 |
| Number of pages | 13 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 15 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jan 25 2023 |
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. Ion irradiations were performed at the Ion Beam Materials Laboratory (IBML), located at the University of Tennessee, Knoxville campus. APT research was supported by the Center for Nanophase Materials Sciences (CNMS), a US Department of Energy Office of Science User Facility at Oak Ridge National Laboratory. The authors thank James Burns for his assistance in performing APT sample preparation and running the APT experiments. High-resolution atomic imaging work was through the Laboratory Directed Research and Development Program at Idaho National Laboratory under the Department of Energy (DOE) Idaho Operations Office (an agency of the U.S. Government) Contract DE-AC07-05ID145142. The authors thank Jatuporn Burns for her assistance in performing TEM sample preparation for high-resolution imaging.
| Funders | Funder number |
|---|---|
| Center for Nanophase Materials Sciences | |
| U.S. Department of Energy | |
| Office of Science | |
| Basic Energy Sciences | DE-AC05-00OR22725 |
| Oak Ridge National Laboratory | |
| Laboratory Directed Research and Development | |
| University of Tennessee | |
| Idaho National Laboratory | |
| Idaho Operations Office, U.S. Department of Energy | DE-AC07-05ID145142 |
Keywords
- atom probe tomography
- density functional theory
- hardening
- high-entropy alloys
- nanoprecipitates
- radiation
- swelling
- transmission electron microscopy