Effect of laser remelting and ultrasonic irradiation on crack suppression and properties of Ni-WC laser cladding layer
摘要
This study investigates crack suppression mechanisms in Ni60-WC laser cladding layers on C45E4 steel using ultrasonic irradiation and laser remelting. C45E4 steel, widely used in industrial gears and shafts, suffers from wear and corrosion in heavy-load environments. Laser cladding provides surface reinforcement, but cracks persist due to thermal stress and WC/matrix mismatch. Key findings reveal that ultrasonic cavitation breaks dendrites through micro-jet impacts, while acoustic streaming homogenizes the melt pool, reducing elemental segregation. Laser remelting eliminates cracks by remelting defect-prone regions (e.g., interfacial porosity) and releasing residual stress through thermal equilibrium. The experimental findings demonstrated that ultrasonic waves significantly enhanced the crystal strengthening effect of the fused cladding, resulting in a 17.54% increase in hardness. Furthermore, the combined laser remelting and ultrasonic-assisted process effectively prevented crack formation in the cladding layer and enhanced the hardness of the substrate. Despite partial WC dissolution, hardness improvements remain significant due to grain refinement. This dual-assisted strategy demonstrates practical value for repairing C45E4 components in mining and energy equipment.