Reaction processes of the titanium matrix composites fabricated from Ti-Al-B 2 O 3 system

Titanium matrix composites reinforced with α-Al2O3 and TiB2 particles were fabricated by in situ synthesis from a Ti-Al-B2O3 system. The reaction processes and microstructure were analyzed by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that the reactions in the Ti-Al-B2O3 system can occur spontaneously and consist of three steps: 1) 15Al + 7B2O3 → 7α-Al2O3 + AlB12 + 2B; 2) 14B + 2Al → AlB12 + AlB2 and 3) 7Ti + AlB12 + AlB2 → 7TiB2 + 2Al. The final reinforcements were composed of α-Al2O3 and TiB2 particles, which were uniformly distributed in the titanium matrix.