10th International Conference on Surface Engineering (ICSE 2026)

Cracking remains a major limitation to the structural integrity and engineering application of Cr₃C₂/NiCr laser-cladded coatings. In this work, the crack formation mechanism and process regulation strategy were systematically investigated by integrating the representative L3 coating from conventional laser cladding with a comparative study of conventional laser cladding (LC) and composite induction-assisted laser cladding (CILC). The L3 coating exhibited severe Cr-rich carbide segregation, strong crystallographic anisotropy, significant local strain accumulation, and the highest microhardness, providing a representative state for elucidating crack initiation and propagation. EBSD analysis revealed that crack-adjacent regions were characterized by elevated KAM values, with a peak of 4.97°, while Cr₇C₃ exhibited a maximum texture intensity of 83.94 MUD. The coexistence of brittle carbide-rich regions and the ductile γ-(Fe,Ni,Cr) matrix generated strong mechanical and crystallographic heterogeneity, promoting localized stress concentration and cleavage-dominated fracture. In contrast, CILC introduced substrate preheating and electromagnetic stirring, which suppressed carbide segregation and directional growth, promoted grain refinement and compositional homogenization, and substantially reduced porosity. The peak microhardness increased from 692.1 HV_0.2 for LC to 1485.8 HV_0.2 for CILC, while the average friction coefficient decreased from 0.66 to 0.56. The corrosion potential increased from −0.740 to −0.579 V, and the corrosion current density decreased from 17.31 to 0.271 μA cm⁻². These results demonstrate that crack formation is governed by the coupled effects of carbide heterogeneity, crystallographic anisotropy, and local strain localization, whereas thermal-electromagnetic process regulation provides an effective route for homogenizing the microstructure and improving the overall performance of Cr₃C₂/NiCr coatings.
 

Cr3C2/NiCr, composite induction laser cladding, crack propagation, process regulation