Formation rules of single phase solid solution in high entropy alloys

A new empirical rule to form single phase solid solution structured high entropy alloys was proposed by integrating three dependent parameters, i.e. atomic size difference δ, mixing enthalpy Δ H mix and valence electron concentration VEC. It was found that the single phase face centred cubic solid solution will form if δ < 4.27, − 7.27 kJ mol − 1 < Δ H mix < 4 kJ mol − 1 and VEC>8, while the single phase body centred cubic solid solution will form in the case of δ < 4.27, − 7.27 kJ mol − 1 < Δ H mix < 4 kJ mol − 1 and VEC < 6.87. This empirical rule was verified by typical high entropy alloys that have been reported.