Hi everyone, I read a journal paper (titled: Entropy-driven phase stability and slow diffusion kinetics in an Al0.5CoCrCuFeNi high entropy alloy) in which the authors (Chun Ng et al.) after thermo-mechanical treatment of the alloy at 700, 900 and 1100 degree Celsius, made the following statement: "The phases we obtained after annealing at 700, 900 and 1100 degree Celsius are actually the equilibrium ones at these corresponding temperatures, and they are frozen to the room temperature, as the annealing of HEAs is somehow equivalent to a quenching process for conventional alloys."

This means that if you have the Isopleth phase diagram of this alloy and it shows that FCC, BCC and sigma phases are stable at a temperature of 700 degree Celsius, annealing the alloy (as-cast sample with maybe FCC phase only) would give rise to FCC, BCC and sigma as the final phases in the alloy.

What is the implication of the authors' statement on the design of HE alloys for high temperature applications?

HEAs Isopleth phase diagrams are usually produced at high temperatures (500 and above). Does that mean an as-cast alloy will have single solid solution phase (say FCC) if the Isopleth Phase diagram shows FCC phase below the Liquidus temperature?