A thermodynamic description of the Al–Cu–Fe–Mn system for an immiscible medium-entropy alloy design

A thermodynamic description of the Al–Cu–Fe–Mn quaternary system has been developed for the design of high-strength immiscible dual-phase medium-entropy alloys. A new thermodynamic assessment for the Al–Cu–Mn ternary sub-system is performed, covering the entire composition range. Thermodynamic parameters of B2 and AlCuFe_τ and φ phases in the Al–Cu–Fe ternary sub-system are also revised based on a previous description that used different constituent binary descriptions. The reliability of the developed thermodynamic description for the Al–Cu–Fe–Mn quaternary system is experimentally confirmed by designing, fabricating, and analysing the phase structures of Al–Cu–Fe–Mn medium-entropy alloys.