Effect of Mo addition on microstructure and wear resistance of laser clad AlCoCrFeNi-TiC composite coatings

As a typical wear-resistant material, TiC particle-reinforced AlCoCrFeNi composite coatings have great advantages. In this work, the Mo was added to AlCoCrFeNi-TiC coatings to further improve the wear resistance, which were fabricated as AlCoCrFeNiMox-TiC (x: molar ratio; x = 0, 0.2, 0.5, 0.8) composite coatings by laser cladding. The microstructure evolution, hardness, and wear resistance were investigated in detail. The results show that a ring of (Ti, Mo)C phase is formed in the outer layer of TiC particles due to the substitution of Mo atoms. Based on the first-principles calculations, the lattice constant of (Ti, Mo)C phase is 4.328 Å, slightly smaller than that of TiC. More importantly, Mo can significantly reduce the interface energy from 0.27 J·m−2 to − 0.18 J·m−2, thus improving the interface stability. The coating matrix (CM) exhibits a spinodal structure of B2 + σ phase, caused by the generation of σ phase. The σ phase has a calculated hardness of about 15.3 GPa, which is undoubtedly conducive to wear resistance of the CM. With the addition of Mo, the hardness of composite coating increases from 611.9 HV0.3 to 822.6 HV0.3. All the coatings present high wear resistance, as evidenced by the abrasive wear mechanisms.