Single-phase equiatomic Co-Cr-Fe-Ni high-entropy alloy with excellent strain gauge sensitivity

Single-phase Co-Cr-Fe-Ni high-entropy alloys boast exceptional mechanical and electrical properties. These alloys are suitable for various functional applications, particularly as strain gauges and high ohmic resistors, due to this fact. The resistance-tension tests of the equiatomic CoCrFeNi high-entropy alloy demonstrate higher strain gauge factor (GF) and elastic limit values than commercial strain gauges. In the elongation range of ε = 0–0.2%, the resistivity of the studied alloys follows a strictly linear pattern with respect to the applied load, up to 435 MPa. Heat treatment enhances the GF value of the as-cast alloy from 3.07 to 3.45. The annealing process changes the sample structure, resulting in an increase in the GF.