High-temperature oxidation resistance of a Ti-Al-Sn-Zr titanium matrix composites reinforced with in situ TiC and Ti5Si3 fabricated by powder metallurgy

A mixture of the Ti-Al-Sn-Zr matrix powder and SiC particles was used as a raw powder to fabricate an in situ TiC and Ti5Si3 reinforced titanium matrix composites (TMCs) via low energy ball milling-cold press forming-argon-protected sintering. The effects of various content of SiCp on the microstructure, phase composition and high-temperature oxidation behavior of the composites at 750 degrees C and 850 degrees C were studied. XRD results show that the oxidation phases were mainly composed of TiO2, Al2O3, SiO2 and alpha-Ti. According to the SEM images, the cross-sectional morphology of oxidation at 750 degrees C for 100 h shows that the oxide layer (20.00 mu m) in the TMCs with 10.0 vol% SiCp after oxidation was denser and thinner and was 82.13% thinner than that of the matrix (98.00 mu m). The parabolic rate constant (k(p)) of the oxidized composites decreases with the increase of SiCp content at 750 degrees C and 850 degrees C. In particular, the composites with 10 vol% SiCp content have smaller k(p). All the results show that the addition of SiCp in TMCs can improve high-temperature oxidation resistance.