Ti2AlC/TiAl Composites with Doped Ti3AlC2 by SPS

Ti3AlC2 ceramics were fabricated by in-situ reaction in the 2TiC-Ti-1.2Al system. The Ti2AlC/TiAl composites were prepared by spark plasma sintering in the 59.2Ti-30.8Al-10Ti(3)AlC(2) (wt%) system. The phase composition and microstructure of the products were analyzed by XRD and SEM, respectively. The room temperature mechanical properties were also measured. The results reveal that the in-situ heat pressed Ti3AlC2 materials are composed of Ti3AlC2 and TiC phases. Ti3AlC2 ceramics present layered structure and TiC particles distribute around the grain boundaries. The Ti2AlC/TiAl composites prepared by SPS are mainly composed of TiAl, Ti3Al and Ti2AlC phases. Ti2AlC reinforcements are mainly distributed in the matrix grain boundaries, which exhibit the grain-boundary strengthening or intracrystalline strengthening effect. The density, Vickers hardness, fracture toughness and flexural strength of the Ti2AlC/TiAl composites are 3.85 g/cm(3), 5.37 GPa, 7.17 MPa(.)m(1/2) and 494.85 MPa, respectively. The fracture features such as transgranular, intergranular and lamellar tearing play an important role in improving the performance of the composites.