Promising elevated temperature mechanical properties of novel lightweight Fe47Mn25Al13Cr7Ni5C3 medium-entropy alloy

Abstract

In this study, a novel lightweight Fe47Mn25Al13Cr7Ni5C3 medium-entropy alloy (MEA) with promising mechanical properties from room temperature to 800 °C was designed. The MEA exhibited sluggish diffusion kinetics and excellent thermal stability. The activation energy required for the microstructural evolution was comparable to that of a Inconel 718, which is a representative Ni-based superalloy. Furthermore, the addition of aluminum and nickel precipitated an ordered body-centered cubic phase, predominantly at the grain boundaries, effectively hindering dislocation movement and deformation of grain boundaries at room and elevated temperatures. The room and elevated temperature mechanical properties of the designed low density MEA (theoretical density of 6.803 g/cm3) exceeded those of Fe-based superalloys and are even better than those of the Ni-based superalloys. In addition, the proposed MEA was cost-effective because of the use of low-cost principal elements, such as Fe, Mn, and Al. The proposed MEA and its alloy design strategies for lightweight and cost-effectiveness offer the potential to achieve structural materials as alternatives to conventional superalloys for application over a wide temperature range. © 2024 Elsevier B.V.