Diffusion, Intrusion and Reaction between Al-Containing Intermetallics and TiC Sintered Body during Thermal Pressure Holding

Intermetallics of Fe40Al, Ni3Al and TiAl(NbCr) were used as matrix to effectively bond a layer of TiC sintered body with low porosity. The coupled intermetallic and the TiC sintered body were held at high temperatures and a given pressure. The microstructure of the interface was observed and analyzed by scanning electron microscopy (SEM) and energy dispersive spectra (EDS). The results show that the bond between the intermetallics and the TiC sintered body is a metallurgical bond. TiC slightly decomposes and diffuses into the surface layers of Fe40Al and Ni3Al during the holding time, resulting in decrease of their melting points, and hence the intermetallic is in a flowing state and intruded into the pores of the TiC sintered body at the interface. However, the TiAl(NbCr) alloy can not be intruded into the pores of TiC sintered body; instead, a distinct reaction layer with more than 10 at% Ti (higher compared with the matrix) is formed at the interface of the TiAl(NbCr) alloy and the TiC sintered body.