Triple-wire plasma arc cladding of Cr-Fe-Ni-Tix high-entropy alloy coatings

High-entropy alloys (HEAs) are promising coating materials for wear resistance applications. However, the preparation of HEA coatings with powder has the disadvantages of high cost and low efficiency. In this study, an innovative triple-wire plasma arc cladding (TW-PAC) method was used to prepare HEA coatings. Nonequiatomic Cr-Fe-Ni-Tix (x is Ti wire feeding speed, x = 0, 0.5, 0.8 and 1.0 m/min, denoted as Ti0, Ti0.5, Ti0.8 and Ti1.0) HEA coatings were successfully prepared by using three commercial wires (ERTi-2, ER304L and Cr20Ni80 wire). With increasing Ti content, the structure of the Cr-Fe-Ni-Tix HEA coatings changed from the single FCC phase to the FCC + γ′ (Ni3Ti) + Laves (Fe2Ti) phase, and the microhardness of the coatings increased from 137 HV to 873 HV. Due to the addition of Ti, Ni3Ti and Fe2Ti phases with high hardness precipitated in the alloy coating, accompanied by the solid solution strengthening effect of the FCC phase, the wear resistance of the coatings was significantly improved (from 9.67 × 10−4 to 1.49 × 10−4 mm3/N·m). The results of this study contribute to the preparation of thick HEA coatings overlarge areas at low cost and with high efficiency and provide new insights into Cr-Fe-Ni-Tix HEA coatings.