Developing New Type of High Temperature Alloys–High Entropy Superalloys

Abstract

Novel high temperature alloys – high entropy superalloys (HESA) have been developed by elevating the mixing entropies of Ni-Al-Co-Cr-Fe-Ti systems, these alloys contain stable FCC γ matrix and L1 2 γ' precipitates; compositions spaces are outside the scopes of traditional Ni-base superalloys and equimolar high entropy alloys. The thermal stability of high entropy γ' precipitates can be enhanced through alloy design by thermodynamic calculation based on Thermo-Calc. HESAs have potentials to high temperature structural application; alloy densities are below 8.0 g/cm 3 with lower cost of raw materials than those of conventional Ni-base superalloys.