Microstructure and Mechanical Properties Investigation of Ni35A-TiC Composite Coating Deposited on AISI 1045 Steel by Laser Cladding

Abstract In this research, the TiC-Ni35A composite coating was fabricated on the AISI 1045 steel substrate by laser cladding process. The cross-sectional morphology, microstructure, micro-hardness, and wear resistance of coatings obtained under different laser energy densities (E) and TiC powder ratios (PR) were analyzed. According to the results, all the coating had a reliable metallurgical bonding with the AISI 1045 steel substrate. The X-ray diffraction (XRD) analysis revealed that the coating phases were Ni and TiC. The average microhardness of the Ni35A-80wt.% TiC coating reached up to 75.12 HRC. The minimum coefficient of friction of the composite coating was only about 30% of the AISI 1045 substrate. The wear form was mainly adhesive wear when altering the TiC powder ratios, while the wear form also contained abrasion wear under different energy densities. The ability of decomposition and re-nucleation of TiC was significantly improved with the increase of laser energy densities and the decrease of TiC powder ratios. The micro-hardness, wear resistance, and coefficient of friction of the composite coating were improved because of the TiC strengthening phase particles. Compared with the AISI 1045 steel substrate, the micro-hardness and wear resistance of the composite coating was increased by 5.29 times and 6.26 times, respectively.