Microstructure of TiAl/TiC cermet joint bonded by combustion synthesis
(1.State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology,Harbin 150001, China2.哈尔滨工业大学 现代焊接生产技术国家重点实验室, 哈尔滨 150001)
Abstract: TiAl alloys were joined to TiC cermets using combustion synthesis method. The Ti-C-Ni metallic powder compact acted as a joining interlayer in the joining process. The identification and mechanisms of the reaction at the interface and interlayer were investigated. From the analysis of the microstructure of TiAl/TiC cermet joint, it is noted that TiC and TiNi compounds are main reaction products and unreacted Ni is observed in the interlayer. The reaction products consist of a large volume of voids or unreacted regions. It is confirmed that Al addition as well as joining pressure are effective to decrease the voids. It is considered that high flowability of liquid Al enhances the SHS reaction and the densification of reaction products. There is a continuous Ni-rich layer observed at the interface between the interlayer and TiC cermets substrate. Ti3Al, TiC and TiNi compounds are observed in the reaction products.
Key words: TiAl alloys； TiC cermets； join； combustion synthesis； microstructure