Role of alloying on tunability of martensitic phase transformation in multi-principal element alloys*

Multi-principal element alloys (MPEAs) are an intriguing class of materials where structure and property relations can be controlled via chemical disorder. Employing density-functional theory, we tuned free energies between f.c.c. and h.c.p. phases using disorder in Fe-Mn-Co-Cr based MPEAs to show that free-energy difference and stacking-fault energy directly correlates with martensitic phase transformation and chemical short-range order. The prediction of possible martensitic transformation at specific Fe composition, i.e., x=40at.% in Fe_xMn_80-xCo₁₀Cr₁₀, offers an understanding of electronic level physics driving transformation-induced plasticity. This also establishes the relevance of theory-guided design for the next-generation alloys with superior structure-property correlation and provides unique insights for controlling phase transformation in technologically relevant alloys.