Microstructure and mechanical properties of SiC-reinforced Inconel 718 composites fabricated by laser cladding

Laser cladding provides the feasibility for fabricating various ceramic-reinforced metal-matrix composite coatings, where the reinforcement content plays a critical role in influencing the residual stresses and the performance of the cladded layer. In this paper, the SiC-reinforced Inconel 718 composites are prepared by LC, and the microstructure and mechanical properties (stress distribution, microhardness, wear behavior) of the cladded layers with different SiC contents are investigated. Based on multi-physics modeling complemented by experimental validation, the thermal stress distribution is analyzed and the residual stresses of the formed Inconel 718/SiC are investigated. The addition of an appropriate amount of SiC can help to relieve residual stresses in the clad layer, with the layer containing 5 wt% SiC corresponding to the minimum residual stress. Moreover, the addition of ceramic particles is conduced to refine the microstructures, and metallic carbides generated by the decomposition of SiC in combination with the diffused elements of the matrix play a positive role in the hardness improvement. The wear resistance of the coatings also increases significantly with increase of SiC content, and the wear mechanism is dominated by abrasive wear, accompanied by oxidation wear, fatigue wear and adhesive wear.