Abstract
Direct experimental observations of chemical short-range order (SRO) in complex concentrated alloys (CCAs) have triggered high interest. However, the reported effects of SRO on yield stresses are controversial, and their atomic-scale mechanisms are elusive, which limits our ability to utilize SRO in alloy design. Here we tackle this challenge using an advanced computational approach that rigorously takes into account the critical lattice distortion in CCAs and further verify our theoretical predictions with experiments. We show that the CoCrNi model alloy has a narrow temperature window around 670 °C for SRO formation. This explains why the mechanical effect of SRO is observed in some experiments but not in others. We propose an effective alloy-doping method to control SRO and reveal atomic-bonding types that dominate SRO formation for different alloys. The strategies and insights generally apply to a broad spectrum of alloys, laying the foundation for designing advanced alloys by manipulating their SRO.
| Original language | English |
|---|---|
| Article number | 120713 |
| Journal | Acta Materialia |
| Volume | 286 |
| DOIs | |
| State | Published - Mar 1 2025 |
Funding
Part of this work was sponsored by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. This research used resources of the Oak Ridge Leadership Computing Facility, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. The experimental work is supported by US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division , under contract no. DE-AC02-05-CH11231. Work at the Molecular Foundry was supported by the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under contract no. DE-AC02-05CH11231. We thank Dr. Ruopeng Zhang who generously shared his experimental results. Dr. Ruopeng Zhang performed the experimental characterization under the supervision of Prof. Andrew M. Minor and Prof. Robert O. Ritchie. Their experiment was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division , through the Damage-Tolerance in Structural Materials program (KC13) at the Lawrence Berkeley National Laboratory (LBNL) and the Molecular Foundry at LBNL under contract no. DE-AC02-CH11231. PKL very much appreciates the supports from the National Science Foundation (No. DMR-1611180 and 1809640 ) and the Army Research Office (No. W911NF-13-1-0438 and W911NF-19-2-0049 ). We thank Dr. Binlun Yin for kindly sharing the compiled yield stresses for CrCoNi. We are also grateful to Prof. Mark Asta and Prof. Dierk Raabe for constructive comments.
Keywords
- Annealing temperature
- Complex concentrated alloys
- Short-range order
- Yield stress