Effects of Ti3SiC2 on microstructure and properties of TiC0.4 enhanced TiAl matrix composites

Abstract

TiC0.4 enhanced TiAl matrix composites with different Ti3SiC2 content were prepared by spark plasma sintering. The microstructure, mechanical properties and tribological properties of TiC0.4 reinforced TiAl matrix composites with different Ti3SiC2 contents were studied systematically. The results showed that with the increase of Ti3SiC2 content, the density of the composites increased and then stabilized, the hardness decreased slightly, and the compressive strength increased at first and then decreased. The density of the material was 4.00–4.02 g/cm−3, the hardness was 4.99–5.01 GPa, and the compressive strength at room temperature and 550 °C was 335–641 and 890–1083 MPa, respectively. When the mass fraction of Ti3SiC2 is 20 wt% and the mass fraction of TiC0.4 is 15 wt%, the tribological properties of TiAl matrix composites are the best. The friction coefficients at RT and 550 °C were 0.485 and 0.440, and the wear rates are 0.10 mg m−1 and 0.015 mg m−1. At room temperature, the friction and wear between hard particles and friction surface in TiAl matrix composites form small grooves. The Ti2AlC formed by the added TiC0.4 and the matrix played a role in wear resistance, while the added Ti3SiC2 can form a lubricating layer and play a good lubricating role.