Effect of Laser Power on the Corrosion and Wear Resistance of Laser Cladding TC4 Alloy

TC4 alloy coatings were fabricated on a titanium alloy substrate using laser cladding. The influence of laser power ranging from 1000 W to 2200 W on the microhardness, wear resistance, and electrochemical corrosion behavior in 3.5% NaCl solution was systematically investigated. Results demonstrate that the TC4 coating exhibited a 35.17% enhancement in microhardness compared to the substrate, with an average value reaching 500 HV. As the laser power increased from 1000 W to 2200 W, the maximum wear depth progressively decreased, indicating significantly improved wear resistance, with fatigue wear being identified as the dominant mechanism. The coating prepared at 1400 W showed the best corrosion performance, displaying the highest self-corrosion potential of −0.110 V, the lowest corrosion current density of 0.125 μA·cm−2, and the largest polarization resistance of 2.057 × 106 Ω·cm2. The charge transfer resistance initially increased and then decreased with increasing laser power. Numerical simulations revealed that when exposed to seawater, galvanic couples formed between the α and β phases on the TC4 titanium alloy surface, resulting in preferential dissolution of the β-phase.