Microstructure and Tribological Performance of Laser Cladding Ti2AlC Particle Reinforced Coatings on Ti6Al4V.

By applying the TC4-Ti₂AlC composite coatings to the Ti6Al4V substrate by laser, the wear resistance of the Ti6Al4V alloy was improved. Analysis was done on the composite coatings' microstructure, phase composition, microhardness, and tribological characteristics. According to the findings, coatings without defects can be created when Ti₂AlC content ranges between 5 and 15 wt.%. Furthermore, the coating without Ti₂AlC consisted of a α-Ti solid solution while coatings with Ti₂AlC included a α-Ti solid solution, hard phases of TiC and Ti₃Al, as well as a Ti₂AlC ceramic phase. During laser cladding, Ti₂AlC partially dissolved and turned into TiC and Ti₃Al, resulting in an average hardness of 371.61 ± 3.95 HV_0.5, 382.92 ± 3.61 HV_0.5, 388.91 ± 3.29 HV_0.5 for the coatings with Ti₂AlC weight fractions of 5, 10, and 15%, respectively. These numbers were about 1.16 ~ 1.22 times the hardness of the titanium alloy matrix (320 ± 3.12 HV_0.5). Besides, the Ti₂AlC lubricant and hard phases act synergistically to bring composite coatings better performances in wear resistance and friction reduction compared to the pure TC4 coating. The lowest coefficient of friction (0.382) (COF) and the greatest wear resistance (8.87 × 10⁻⁵ mm³/N m) were obtained at the composition of TC4-10wt.%Ti₂AlC; more particularly, the wear resistance at TC4-10wt.%Ti₂AlC was 1.2–2.1 times that of pure TC4 coating. The principal causes of wear in a pure TC4 coating are adhesive wear and oxidation, however, these wear processes shift to minor abrasive wear and oxidation when assisted by oxide coatings, Ti₂AlC lubricant, and TiC, Ti₃Al hard phases. [ABSTRACT FROM AUTHOR]