Microstructural evolution and high-temperature wear resistance of novel TiC cermet coatings with CoCrFeNiMo0.1 high-entropy alloy binder fabricated by laser powders directed energy deposition

Abstract

The CoCrFeNiMo_0.1 high-entropy alloy (HEAs)-coated TiC cermet powders, abbreviated as TiC@HEAs, were synthesized via spray granulation. Subsequently, CoCrFeNiMo_0.1 coatings reinforced with varying contents of TiC@HEAs were fabricated using laser powder directed energy deposition (LP-DED). The microstructures of the LP-DED coatings consisted of unmolten TiC@HEAs particles, a transition region, and a (Ti, Mo)C precipitates region. As the content of TiC@HEAs increased, the TiC@HEAs particles gradually agglomerated, and the (Ti, Mo)C precipitates became coarser and more segregated. Furthermore, the hardness of the coatings significantly improved with increasing TiC@HEAs content at both room temperature and elevated temperatures. Specifically, at room temperature, the hardness increased from 201HV to 612–687HV; at 650°C, it increased from 178HV to 601–675HV; and at 850°C, it increased from 118HV to 528–510HV. The elevated-temperature hardness values indicate excellent high-temperature resistance. The coating containing 30 % TiC@HEAs exhibited the highest hardness and the best wear resistance at 650°C, with abrasive wear being the dominant wear mechanism. In contrast, the coating with 10 % TiC@HEAs demonstrated the highest hardness and good wear resistance at room temperature, with adhesive wear being the primary wear mechanism. Additionally, the incorporation of TiC@HEAs reduced friction. This study holds significant potential for expanding the high-temperature applications of HEA-based cermets, offering reliable solutions for manufacturing hot-rolled rolls, composite plates, and other heat-resistant materials.