In-situ composite coating on powder metallurgy master alloy fabricated by vacuum hot-pressing sintering technology

摘要

A material consisting of an in-situ titanium carbide reinforced nickel-aluminide (Ni3Al) coating and a powder metallurgy master alloy was fabricated by vacuum hot-pressing sintering technology. A metallurgical bonded, pores-free interface between composite coating and powder metallurgy master alloy was formed at the sintering temperature of 1050 degrees C, pressure of 10(-4) Pa and pressing pressure of 40MPa. The phase, microstructure and wear behavior of composite coating were investigated. The results showed that polygonal titanium carbide particulates with various sizes were homogeneously distributed in nickel-aluminide matrix. The sintering temperature, pressing pressure and heat from as-reactions-formed coating green compact facilitated the pore infiltration with transiently generated liquid phases and ensured the high-intensity metallurgical bonding between composite coating and powder metallurgy master alloy. Due to the abnormal elevated-temperature properties of nickel-aluminide matrix, titanium carbide particulates reinforcement and the mechanically mixed layer protection, TiC/Ni3Al-coated parts demonstrated superior wear resistance and lower friction coefficient while compared with Ni3Al-coated parts and H13 steel.