Oxydation à haute température d’un nouvel alliage de titane α+β

Abstract

A new α+β titanium alloy Ti-Mo_4.84-Ta_4.34 alloy named TMT has been oxidised under an atmospheric pressure of oxygen above the α ↔ β transformation temperature. The oxidation resistance increases strongly as compared to pure titanium (almost 50 %), which is mainly due to both alloying elements. The oxygen dissolution involves the α phase precipitation from the β phase, which becomes enriched with Ta and Mo. The diffusion takes place along α precipitates, whose orientations may depart from the normal to the surface. Diffusion is also discussed with regards to phase stability and our results are compared to literature data.