In-situ Formation of TiC Reinforced Intermetallic-Matrix Composite Layers Produced by Laser Cladding

摘要

Laser cladding technique was used to form Ni_3(Si,Ti) intertnetallic composite coating reinforced by in-situ formation TiC particles on Ni-based superalloy substrate. The experimental results showed that an excellent bonding between the coating and the substrate was ensured by a strong metallurgical interface. The clad coating was very well and free from cracks and pores. By means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD), the effect of Ti-C addition to the microstructure and microhardness of the coating was investigated. The microstructure of the coating was mainly composed of Ni(Si), Ni_3(Si,Ti) and TiC. The average microhardness of the coating was improved with increasing the Ti-C content. The microhardness was up to 780Hv when Ti-C addition was 20 vrt. pet, which was much greater than that of Ni-based superalloy substrate.