Effect of pre-oxidation on the high-temperature oxidation behavior of ceramic particles-reinforced TiAl alloy

A TiAl composite containing multiple ceramic particles (Ti₂AlC and Ti₅Si₃) was fabricated via spark plasma sintering (SPS). The effects of pre-oxidation treatment on cyclic oxidation behavior of TiAl composite were systematically investigated, as well as the positive role of ceramic particles was revealed. Pre-oxidation treatment was conducted at 950 °C for 100 min, resulting in the formation of a dense oxide layer (Al₂O₃) and a transition zone (Ti₅Al₃O₂) on the surface of the TiAl composite. Ultimately, a dramatic increase in oxidation resistance was achieved in the TiAl composite during cyclic oxidation, which was attributed to the dense Al₂O₃ layer significantly hindering atomic diffusion. The functional role of the ceramic particles lies in facilitating the formation of the Al₂O₃ layer, modulating the coefficient of thermal expansion mismatch between the matrix and Al₂O₃ layer, suppressing the formation of α₂-Ti₃Al(O), and hindering the decomposition of Ti₅Al₃O₂.