A sustainable route to manufacture refractory high entropy alloy of AlMoNbTaTiZr from metal powder produced in solid state

To enhance efficiency and reduce CO2 emissions in applications such as jet-engines, gas turbines, and nuclear powerplants, alloys that withstand high temperatures are essential. High entropy alloys (HEA) containing refractory elements offer superior high-temperature properties. One of these refractory high entropy alloys (RHEAs) is AlMo0.5NbTa0.5TiZr. There are challenges when manufacturing these compositionally complex alloys using conventional techniques since they have elements with very high (Nb, Ta, Mo), high (Zr, Ti) and lower (Al) melting temperatures, creating mixing and homogeneity issues in alloy preparation. The Fray-Farthing-Chen (FFC) Cambridge process directly creates RHEA’s powders without melting, but these feedstocks require a suitable consolidation technique. In this work field-assisted sintering technique (FAST), a novel rapid sintering technique, was used to make parts from powder of this alloy produced in solid-state.
Among the process parameters the consolidation temperature had a more profound effect on density. From studied temperatures 1400 °C with a dwell time of 15 minutes produced the highest density level. Such a manufacturing route, occurring at temperatures lower than traditional casting, increases sustainability, and produces a homogeneous microstructure leading to parts with uniform properties and enhanced in-service performance.