Effect of compound alloying on high temperature oxidation resistance property of Ti2AlNb alloy

As one of the important materials for new generation aeroengines, Ti2AlNb alloy has many good properties, including good processability, great comprehensive mechanical properties and low density. In order to widen the application field of Ti2AlNb alloy, the optimization of alloy composition and the control of process and microstructure need to be carried out to further enhance the oxidation resistance property of traditional Ti2AlNb alloy. In this study, the compound method of Mo, Zr, W alloys on traditional Ti-Al-Nb alloy was designed to improve the oxidation resistance property of Ti2AlNb alloy. The oxidation mass gain behaviour, the oxide layer structure, surface oxides and the alloy composition distribution of these Ti2AlNb alloys during the high temperature oxidation process at 750 degrees C and 850 degrees C were analyzed and compared. It is found that the oxidation resistance of Ti2AlNb alloy with Mo alloying element decreases obviously when temperature increases from 750 degrees C to 850 degrees C, while the oxidation resistance of Ti2AlNb alloy with Zr alloying element still keeps excellent; the oxide scale microstructure of these Ti2AlNb alloys is made up of oxidation layer, oxygen enrich layer and interstital affected layer according to the SEM morphology analysis of these cross-sections samples. It is believed that Zr and W alloying elements have the coordination repression effects on the formation of different oxide layers during the oxidation process at 850 degrees C. Therefore, the kind of Ti2AlNb alloy with both Zr and W alloying elements was recommended as the promising anti-oxidation Ti2AlNb alloy.