Abstract
Chemical short-range order (SRO) is known to alter a wide array of alloy properties. Here, we investigate the SRO of binary and ternary alloys in the Cr–Mo–W system using density functional theory (DFT) calculations, coupled with Monte Carlo simulations and two distinct approaches: the real-space cluster expansion (CE) and a machine learned interatomic potential (MLIP) based on the moment tensor potential (MTP) form. The size-mismatched binary, Cr–W, exhibits phase-separating long-range order (LRO) in the phase diagram, but surprisingly, the SRO is predicted to be ordering-type from both CE and MTP. We rationalize this apparent discrepancy by accounting for the large coherency strain present in this system, which significantly suppresses the coherent phase-separating tendency relative to the incoherent phase diagram. This competition between LRO and SRO persists in the ternary Cr–Mo–W system, where we find that SRO tendencies can qualitatively differ from those in the corresponding binary alloy. The real-space CE can efficiently capture the correct nearest neighbor SRO tendencies in this system, despite failing to account for long-range strain effects, provided it is trained on the energies of sufficiently large structures to capture short-range strain contributions over the nearest neighbor ranges; however, we suggest MTP, or more generally MLIP, may provide a more general approach for comprehensive studies in disordered alloy systems, especially in medium- and high-entropy alloys exhibiting large lattice mismatch.
| Original language | English (US) |
|---|---|
| Article number | 120199 |
| Journal | Acta Materialia |
| Volume | 277 |
| DOIs | |
| State | Published - Sep 15 2024 |
Funding
NS and CW acknowledge support of this research from the Office of Naval research, Multidisciplinary University Research Initiative program, \u201CFrom Percolation to Passivation (P2P): Multiscale Prediction and Interrogation of Surface and Oxide Phenomena in Multi-Principal Element Alloys\u201D under Grant Number N00014-20-1-2368. TL acknowledges support from Toyota Research Institute PO-002171 Agmt 4/26/22. YX acknowledges support from the US Department of Commerce and National Institute of Standards and Technology as part of the Center for Hierarchical Materials Design (CHiMaD) under award no. 70NANB19H005. The authors also acknowledge the computational resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility located at Lawrence Berkeley National Laboratory, operated under Contract No. DE-AC02-05CH11231 using NERSC award BES-ERCAP0023792, Bridges-2 at Pittsburgh Supercomputing Center [101] through allocation DMR160112 from the Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support (ACCESS) program, which is supported by National Science Foundation grants #2138259, #2138286, #2138307, #2137603, and #2138296, the Quest high performance computing facility at Northwestern University which is jointly supported by the Office of the Provost, the Office for Research, and Northwestern University Information Technology.
Keywords
- Ab initio calculation
- Cluster expansion
- Interatomic potentials
- Lattice strains
- Machine learning
- Short-range order
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys