The Influence of Si on the High-Temperature Oxidation of Near-alpha Titanium Alloys

The addition of Si is known to improve the oxidation resistance of pure titanium and titanium alloys. However, most past studies concern the influence of relatively large Si contents (0.35–8 wt%), which is often incompatible with a good ductility because of the presence of Ti₅Si₃ precipitates. This study focuses on the influence of the Si content on the high-temperature resistance of near-alpha alloys from the family of Ti6244 alloy (6% Al, 2% Sn, 4% Zr 4% Mo–wt%) with small proportions of Si. The silicon addition was found to improve the high-temperature oxidation resistance of near-alpha Ti-Al-Sn-Zr-Mo family alloys by decreasing the oxidation rate and the oxide scale thickness, as well by producing a denser oxide scale. Rutile and alumina were detected within the oxide scale by XRD and Raman spectrometry. The presence of Si is associated with the presence of larger quantities of N at the oxide/metal interface.