Achieving the simultaneous enhancement of elevated-temperature strength and ductility while maintaining low cost remains a fundamental challenge in structural materials design. To address aforementioned issue, a type of Co-free multi-principal element alloy (MPEA) was designed utilizing an Fe-Cr-Ni system as the economical matrix in this study. Compared to conventional Ni-based superalloys and reported MPEAs, expensive Co and W were substituted with Mo and V to achieve solid solution strengthening and improve the stability of the microstructural, while Al, Ti and Nb were incorporated to promote high-density γ′ precipitation. The microstructural analysis revealed that recrystallization treatment effectively eliminated dislocation networks, which suppressed the precipitation of α-Cr phases, and promoted uniform γ′ precipitation throughout the grains during aging. Using this method, we have designed a low-cost, high-performance MPEA. At 700 °C, the tensile strength and elongation of this alloy were 947.3 MPa and 19.2%, respectively, comparable to those of as-forged GH4169 alloy, yet at only 43.8 % of the raw material cost of GH4169. Theoretical calculation further confirmed that the primary strengthening mechanism in this alloy is the precipitation strengthening of the γ′ phases.
Wu et al. (2026) studied this question.