Effect of WC content on microstructure and properties of CrFeMoNiTi(WC)(x) high-entropy alloys composite coatings prepared by selective laser melting

摘要

To improve the surface properties of Q235 carbon steels, CrFeMoNiTi(WC)(x) high-entropy alloy composite coatings were fabricated via selective laser melting. The microstructure, wear resistance, and corrosion resistance of the composite coatings were studied. Spherical or near-spherical tungsten carbide (WC) particles are dispersively distributed in the coatings, resulting in the appearance of obvious WC and TiW2C phases. And the composite coatings mainly consist of body-centered cubic (BCC) and face-centered cubic (FCC). When x <= 0.3, the addition of WC enhances the BCC diffraction peak. Microhardness of the composite coatings with WC increases and is much higher than that of the substrate (280.6 HV0.1). The hardness of the CrFeMoNiTi(WC)(0.3) (1005.1 HV0.1) is the highest among the composite coatings. The retained WC particles and BCC acted as load bearers during the friction process, which reduces the wear loss of the composite coating. Also, the anodic protection caused by the corrosion-resistant WC particles and BCC greatly improves the ability of the composite coatings to resist NaCl attack. Hence, CrFeMoNiTi(WC)(0.3) exhibited the optimum wear resistance and corrosion resistance.