Interfacial reaction in Al2O3 fiber reinforced TiAl matrix composite

Al2O3 short fiber (containing 28 vol.% SiO2) reinforced TiAl matrix composite was prepared by spark plasma sintering (SPS). The interfacial reaction mechanism was clarified by thermodynamic and kinetic analyses. The main interfacial phase was Ti5Si3, originated from Ti element of TiAl matrix and Si element of Al2O3 fiber. The activation energy of interfacial layer was 285.1 kJ/mol. In addition, the matrix around the interfacial region was composed of γ-TiAl phase due to the consumption of Ti element in the process of interfacial reaction. However, the formation of mullite phase occurred in the heat-treated Al2O3 fiber and as-sintered composite due to the chemical reaction between γ-Al2O3 and amorphous SiO2 phases.