Microstructure and property analysis of FeAlCuCrNiNbx high-entropy alloy surfacing layer

In order to study the effect of Nb element content on the structure and properties of FeAlCuCrNiNb_x (x = 0.4,0.6,0.8,1.0) high-entropy alloy, the FeAlCuCrNiNb_x high-entropy alloy was prepared on the surface of carbon steel sheet by the technique of gas metal arc welding. The microstructure, phase composition, microhardness, wear resistance and corrosion resistance of surfacing layer were analyzed. The results show that: the surfacing layer of FeCuCrAlNiNb_x high-entropy alloy is composed of Fe-Cr phase-based BCC solid solution and a few of MC eutectic carbide. The structure is a typical dendrite structure, which is composed of gray dendrite (DR) and white interdendrite (ID) structure. For wear resistance, addition amounts of Nb can significantly improve the microhardness and wear resistance of surfacing layer. The optimal properties of surface layer were obtained when the molar ratio of Nb element is 0.8, which maximum microhardness value is 602 HV, the minimum wear is 0.30 g, respectively. For the corrosion performance, with increase of Nb element addtion amounts, the self-corrosion current density become to reduce, the corrosion rate become to slow, and the corrosion resistance enhances. All of these are better than 304 stainless steel. When the molar ratio of Nb element is 1.0, the corrosion resistance of the surfacing alloy is the best.