Development of Light-Weight TRIP/TWIP FCC High Entropy Alloy with High Specific Strength and Large Ductility

In this study we developed a novel (TRIP+TWIP) high entropy alloy (HEA) with specific strength and large ductility. First, by controlling the atomic constitution of 3d transition metals (Cr, Mn, Fe, Co, Ni), designed light-weight TRIP-assisted dual-phase HEA non-equiatomic composition Cr22Mn6Fe40Co26Ni6, which exhibited 5% lighter density than Cantor HEA. Secondly, systematically added Al (a lightweight element (2.7 g/cm3), has size misfit metals, Ferrite stabilizer) up to 5 at.% in Cr22Mn6Fe40Co26Ni6 With increasing content, phase changed from FCC HCP (0 2.0 at.%) single-phase (2.5 3.5 at.%), BCC (4.0 5.0 at.%). particular, (Cr22Mn6Fe40Co26Ni6)97.5Al2.5 Hall-Petch coefficient relatively lower thermal conductivity due its three times larger mismatch (?) HEA, causes superior solid solution strengthening effect. Furthermore, (Cr22Mn6Fe40Co26Ni6)96Al4.0 boundary precipitation phase, 10% higher as well 50% strain, unique TRIP TWIP complex deformation mechanism. This result shows that addition can not only greater chemical complexity multicomponent compositions, but also microstructural increase competing crystalline phases. The confusion effect caused both complexities lets overcome trade-off relationship among conflicting intrinsic properties, such versus ductility (or density). Consequently, these results pave way for new design strategy