Electronic transport in equiatomic CuZrNiTi alloy

High-entropy metallic alloys have interesting functional properties, which make them promising materials for advanced applications. Influence of configurational entropy on structure formation, glass-forming ability and properties of such alloys is still an open issue. Here we study electronic transport in equiatomic high-entropy CuZrNiTi alloy fabricated from binary Cu50Zr50 one by replacing copper and zirconium by the elements with unlimited solid solubility. We prepare both rapidly quenched and annealed samples of this alloy and study their structure, microstructure, electrical, magnetic and thermal properties over a wide temperature range. The quenched sample has a composite structure consisting of crystalline cubic (Pm3¯m) phase embedded in glassy matrix, but the annealed one is a mixture of two crystalline phases with hexagonal (P63/mmc) and orthorhombic (Pbca) lattices. Measuring both thermal conductivity and electrical resistivity of the alloy and analyzing their relation with using the Wiedemann–Franz law, we reveal that annealed sample demonstrates abnormal increase of phonon contribution to the thermal conductivity with increasing temperature. This effect can be explained by phonon-boundary scattering mechanism due to an ultrafine-grained microstructure of the sample. •We systematically studied an equiatomic high-entropy CuZrTiNi alloy.•We examined the alloy samples prepared by different techniques.•We discuss electron and phonon contributions to the thermal conductivity.•The quenched samples demonstrate composite structure and non-metallic resistivity.•The annealed alloys have an ultra-fine microstructure and unique transport properties.