Effects of TiC on the Microstructure and Mechanical Properties of Four Fe-Based Laser Cladding Coatings

Abstract

This study focuses on Fe-based laser cladding coatings containing varying levels of four elements, and the objective is to investigate the influence of TiC addition on the microstructural evolution, microhardness, wear resistance, and corrosion resistance of these Fe-based composite coatings. Fe/TiC composite coatings were prepared by incorporating 20 wt.% TiC into four types of Fe-based coatings. The coatings were characterized using X-ray diffraction (XRD), optical microscopy for microstructural observation, microhardness testing, friction and wear tests, and electrochemical analysis. The results indicate that the phases of the coatings are primarily composed of α-Fe and Cr7C3. Upon the addition of TiC, the TiC and Ni3Ti phases were observed in the coatings. The coatings mainly consist of columnar crystals, dendritic structures, equiaxed grains, and cellular structures, with petal-shaped TiC particles distributed within the coating matrix. TiC effectively enhances the microhardness and wear resistance of the coatings. The average microhardness of the coatings increased from 455.8 ± 20.8 HV0.2 to 802.8 ± 41.6 HV0.2 with TiC addition. Simultaneously, the wear rate of coating A2 decreased from 1.51 × 10−6 g/(N·m) to 1.02 × 10−7 g/(N·m), indicating an order of magnitude improvement in wear resistance. However, TiC destroys the denseness of the Fe coating, the current corrosion density increases by 28% on average, and the corrosion resistance decreases significantly.