Martensitic Transformation in FexMn80-xCo10Cr10 High-Entropy Alloy
Iowa State University Digital Repository, Ames IA (United States)
Is Version Of
Materials Science and EngineeringChemical and Biological EngineeringAmes National LaboratoryPhysics and Astronomy
High-entropy alloys and even medium-entropy alloys are an intriguing class of materials in that structure and property relations can be controlled via alloying and chemical disorder over wide ranges in the composition space. Employing density-functional theory combined with the coherent-potential approximation to average over all chemical configurations, we tune free energies between face-centered-cubic and hexagonal-close-packed phases in FexMn80-xCo10Cr10 systems. Within Fe-Mn-based alloys, we show that the martensitic transformation and chemical short-range order directly correlate with the face-centered-cubic and hexagonal-close-packed energy difference and stacking-fault energies, which are in quantitative agreement with recent observation of two phase region (face-centered cubic and hexagonal closed pack) in a polycrystalline high-entropy alloy sample at x = 40 at.%. Our predictions are further confirmed by single-crystal measurements on a x = 40 at.% using transmission-electron microscopy, selective-area diffraction, and electron-backscattered-diffraction mapping. The results herein offer an understanding of transformation-induced or twinning-induced plasticity in this class of high-entropy alloys and a design guide for controlling the physics at the electronic level.
This article is published as Singh, Prashant, Sezer Picak, Aayush Sharma, Y. I. Chumlyakov, Raymundo Arroyave, Ibrahim Karaman, and Duane D. Johnson. "Martensitic Transformation in FexMn80-xCo10Cr10 High-Entropy Alloy." Physical Review Letters 127, no. 11 (2021): 115704. DOI: 10.1103/PhysRevLett.127.115704. Copyright 2021 American Physical Society. DOE Contract Number(s): AC02-07CH11358. Posted with permission.