Fabrication, Microstructure and Mechanical Properties of TiC/Ti2AlC/TiAl3in situ Composite

This paper described a process for synthesizing a new multiphase TiC/Ti2AlC/TiAl3 composite, in which Ti, Al4C3 and graphite powders were utilized as raw materials, and in situ spark plasma sintering-reactive sintering (SPS-RS) methods were involved. The intermediate phases of Ti3Al and TiAl were found during the reactive sintering process and the reactions for the phase's formation were proposed. The microstructure and mechanical properties of the composites were investigated. The high-resolution transmission electron microscopy (HRTEM) image of the interface showed that no amorphous phases were detected along the grain boundary. The orientation relationships between the Ti2AlC and the TiC were shown to be (0001)Ti2AlC∥(111)TiC and [110]Ti2AlC∥[110]TiC. The average hardness, fracture toughness, Young's modulus and bending strength of the composite were 15.1±0.8 GPa, 4.9±0.3 MPa-m1/2, 261±13 GPa and 776±18 MPa, respectively. The toughening mechanism was also discussed.