The similarity of elements in multi-principle element alloys based on a new criterion for phase constitution

Highlights: • The phase constitution of MPEAs is well predicted by the priori α-${\Delta H}_{\mathrm{mix}}$ criterion. • The similarity of elements in MPEAs is evaluated by calculating the derivative of α and ${\Delta H}_{\mathrm{mix}}$. • The higher the similarity between added and matrix elements, the more stable the phase constitution of the MPEA. Prediction of the phase constitution of the multi-principle elements alloys (MPEAs) with various element numbers is important for alloy design and performance optimization. Herein, valence electron density parameter, $\alpha$, is proposed as an improvement of the valence electron concentration by including the impact of atom volumes. The phase constitution of numerous MPEAs is well predicted by the priori α-${\Delta H}_{\mathrm{mix}}$(enthalpy of mixing) criterion, evidenced by the distinguishing of FCC single phase, FCC and BCC dual-phase and BCC single phase. The similarity of elements in MPEAs is evaluated by the derivative of α and ${\Delta H}_{\mathrm{mix}}$with respect to atomic percentage, which successfully predicts the phase constitution of CrFeNi with addition of Ti, Zr, Al, Cr, Fe, Ni, Co and Cu. This work provides valuable insights into priori judgement of the phase constitution of MPEAs in the view of the relationship between elements.