Search for high entropy alloys in the X-NbTaTiZr systems (X = Al, Cr, V, Sn)

•Composition of refractory high entropy alloys predicted.•Solid solutions found in VNbTaTiZr and AlNbTaTiZr.•Alloys containing Cr and Sn are multi-phased.

High entropy alloys, i.e. solid solution phases, are sought in the X-NbTaTiZr equiatomic system where the X element was chosen as Al, Cr, V and Sn by applying recent criteria based on size and electronegativity mismatch of alloy components, number of itinerant and total valence electrons, and the temperature at which the free energy of mixing changes at the alloy composition. The alloys containing V and Al are mostly constituted by solid solutions in good agreement with prediction.