Significant improvement of the oxidation resistance of MoSiBTiC-based multiphase alloys by Ti enrichment

The effects of the Ti content on the microstructure and oxidation behaviour of Mo–yTi–14Si–6C–6B (atom %) alloys were investigated. Enrichment with Ti of up to 54% did not change the four-phase constitution of the Moss, Mo5SiB2, Ti5Si3, or TiC phase, and improved the oxidation resistance of the alloy. The Mo–50Ti–14Si–6C–6B alloy exhibited the best oxidation resistance at 800–1200 °C through formation of a dense layer of TiO2. This improvement can be described in terms of a modified Pilling–Bedworth ratio, which indicated that the densest TiO2 layer formed on Moss grains.