Tribomechanical properties of direct energy deposited ceramic reinforced coatings on alloy TC4

Abstract In this study, TC4 (Ti6Al4V) surface alloyed with TiC and C powders in varied volumetric ratios utilizing robotic plasma transferred arc (PTA) welding. The coated zone had no microstructural defects like fractures, porosity, or voids, eliminating operator errors – a durable metallurgical bond established between the substrate and coating. X-ray diffraction (XRD) analysis indicated the formation of TiC, VC, and TiV–C ternary compounds during the coating process, with the α -Ti structure frequently seen. Gibbs free energy projections confirm XRD results. Graphite-TiC combination increased hardness 1.3–1.8 times. The sole TiC powder reinforced sample had the maximum hardness (573 ± 159 HV 0.1 ) compared to the substrate (298 ± 11 HV 0.1 ). Coating elasticity modules were calculated. The modulus of elasticity increased up to 2.44 times. The plasticity index accurately predicted sample load and deformation resistance. Sole graphite reinforcement had the lowest friction behavior, and the sole TiC powder-enhanced sample had the maximum wear resistance. The sole TiC-coated sample had an 11.5-fold improvement in wear resistance. Graphite–TiC combined samples improved wear resistance by 2.4–2.67 times. The addition of graphite reduced COF by 55 %. The findings point to a powder mixture with a high graphite content to reduce friction in machine components.