Investigation of TiAl/Ti2AlC composites prepared by spark plasma sintering

TiAl/Ti2AlC composites were produced by spark plasma sintering technology from mixed powders of Ti, Al and TiC. X-ray diffraction (XRD) patterns showed that the sintered products mainly consisted of TiAl and Ti2AlC phases. Electric probe microcosmic analysis (EPMA) photos indicated different microstructures depending on composition. In one case, when 7 vol.%TiC was mixed in the starting powders, the produced Ti2AlC particles were uniformly dispersed in the TiAl matrix with the partial lamellar structure containing γ and lamellar phases (duplex structure). In another case, while 15 vol.%TiC was added, the composites consisted of interpenetrating networks of Ti2AlC and TiAl phases. After the annealing, however, all of them changed to that of Ti2AlC particles dispersed uniformly in the γ(TiAl) matrix. The fracture toughness and bending strength of the composites were tested, respectively.