Study on Microstructure and Mechanical Properties of AlCoCrFeNi High-Entropy Alloy Coating Prepared by Electroplating-Electron Beam Hybrid Cladding

The AlCoCrFeNi high-entropy alloy coatings with single matrix FCC phase and uniform distributions of elements were successfully synthesized on 304 stainless-steel substrate by a two-step surface modification method of electroplating and electron beam cladding, and the microstructure and mechanical properties of the coatings were studied and analyzed. The results indicate that the prepared AlCoCrFeNi high-entropy alloy coating has excellent mechanical properties, and its thickness increases with the increase of electron beam intensity. The highest hardness and elastic modulus of the coating reaches about 2.6 and 1.5 times those of the substrate, respectively, which are ascribed to increased Cr with less dilution from the substrate. The wear rate of the coating first decreases and then increases with increasing electron beam intensity. The best friction and wear properties are obtained in the coating with high hardness and few cracks prepared at an electron beam intensity of 6 mA. The main wear mechanisms of the coatings are abrasive wear and oxidation wear accompanied by slight adhesive wear.