Optimization of the Pulsed Laser Cladding Process to Improve the Wear Resistance of (Ti, V)C/Ni Coatings

Continuous laser cladding of Ni-based composite coatings commonly suffers from coarse microstructures, high residual stress, severe cracking susceptibility, and limited wear performance. Although substrate preheating is an effective strategy for crack suppression, it inevitably induces microstructural coarsening and deteriorates mechanical and tribological properties, while the independent and coupled effects of pulsed laser modulation and preheating on (Ti, V)C/Ni coating performance remain insufficiently quantified and clarified. To address these technical gaps, this work fabricates (Ti, V)C/Ni composite coatings on Cr12MoV die steel via pulsed laser cladding. An L16 orthogonal experiment is employed to systematically investigate the influences of average power, duty cycle, and pulse frequency on coating hardness, and the optimal pulsed laser parameters are determined as 1750 W average power, 65% duty cycle, and 10 Hz pulse frequency. Under optimized parameters, the pulsed-laser-clad coating achieves a maximum hardness of 898.6 HV0.2, exhibiting 10.2% higher hardness and 41.4% better wear resistance than its continuous laser-clad counterpart, owing to the refined microstructure and enhanced grain-strengthening effect induced by rapid pulsed thermal cycling. Further comparative experiments demonstrate that substrate preheating combined with pulsed laser cladding effectively eliminates coating cracks and reduces residual stress by alleviating concentrated thermal strain. Nevertheless, preheating-induced microstructure coarsening slightly reduces the hardness and wear resistance of the composite coating compared with the purely pulsed laser-processed coating. In summary, pure pulsed laser processing dominates the improvement in wear resistance, whereas preheating mainly contributes to defect suppression and stress relief, enabling reliable engineering application of laser-clad coatings.