Microstructure and high-cycle fatigue fracture characteristics of WC-enhanced nickel-based laser cladding coating

Aeroengine and powertrain components operate under elevated temperatures and cyclic loading, making them prone to fatigue failure. Laser cladding (LC) has emerged as a sustainable repair technology due to its strong metallurgical bonding and flexible processing. However, rapid thermal cycles during LC can introduce defects such as pores, cracks, and inclusions that impair fatigue performance. Ni60A alloy is widely used in LC for its excellent processability, and reinforcement with tungsten carbide (WC) enhances wear and fatigue resistance through interfacial bonding, dislocation hindrance, and the formation of hard phases. Despite advances, high-cycle fatigue (HCF) behavior and fracture mechanisms in LC-repaired components remain underexplored-particularly the role of WC particle size, distribution, and interaction with dislocations. This study examines tensile and HCF properties of Ni60A/25%WC laser-clad coatings at room temperature. S-N curves were generated and fracture surfaces analyzed to understand fatigue crack initiation and propagation. Energy-dispersive spectroscopy was used to investigate the influence of WC/W₂C on microstructure and mechanical performance. Our findings highlight how WC particle morphology and distribution affect fatigue resistance, providing insight into fatigue failure mechanisms and establishing a foundation for improved LC repair strategies of critical components in high-performance systems.