Establishing the transformation pathways in Refractory Metal High Entropy Superalloys

Refractory metal high entropy superalloys (RSA) show exceptional promise for high temperature service but the formation pathways that lead to their two-phase A2-B2 microstructures is unestablished. Current proposals include a spinodal process but an ordering reaction must also occur and direct identification of the transformation sequences, along with the key temperatures, is imperative to enabling the further developments of these alloys. Here we propose to use Laue diffraction to conclusively establish the evolution of the microstructure of five RSA during cooling for the first time. These results will not only aid the optimisation of current alloys but will enhance the design of new RSA.