Microstructural evolution and wear characteristics of laser-clad CoCrFeNiMn high-entropy alloy coatings incorporating tungsten carbide

Abstract

CoCrFeMnNi HEA coatings incorporating WC ceramic particles with varying contents (0%, 10%, 20%, 30%, and 40%) are synthesized by laser cladding in this study. The phase evolution, strengthening mechanisms, and dry sliding wear behavior are investigated. The microstructure analysis revealed that coatings with WC content up to 20% consist of a single FCC phase, while those with WC content exceeding 30% exhibit a combination of FCC and polymorphic M3W3C phases. The microhardness increases from 169HV to 517HV with the content of WC varies from 0% to 40%. The contributions of precipitation strengthening and dislocation strengthening are the primary factors driving hardness increment. The presence of M3W3C further contributes to precipitation strengthening, resulting in enhanced hardness with increasing WC content. Moreover, the coating with 30% WC particles exhibits the most superior wear resistance, with a significantly reduced volume wear rate of 2.37 × 10−6 mm3/(N·m), which is merely 0.7% in comparison to the WC-free coating. With increased WC content, the wear mechanism of the coatings shifts from adhesive wear to oxidation wear, attributed to the hierarchical interfaces between the FCC matrix and the WC/M3W3C phase. This study offers valuable insights for enhancing the durability and performance of advanced coatings.