Microstructure and properties of Al ₂ O ₃ -TiC-Ti ₃ SiC ₂ composites fabricated by spark plasma sintering

Highly densified Al2O3-TiC-Ti3SiC2 composites were fabricated by spark plasma sintering technique and subsequently characterised. From fracture surface observation, it is found that Al2O3 is 0·2-0·4 μm, TiC is 1-1·5 μm and Ti3SiC2 is 1·5-5 μm in grain size. With the increase in Ti3SiC2 volume contents, Vickers hardness of the composites decreases because of the low hardness of monolithic Ti3SiC2. The fracture toughness rises remarkably when the contents of Ti3SiC2 increase, which is attributed to the pullout and microplastic deformation of Ti3SiC2 grains. At the same time, the flexural strength of the composites shows a considerable improvement as well. The electrical conductivity rises significantly as the Ti3SiC2 contents increase because of the formation of Ti3SiC2 network and the increase in conductive phase contents.