Influence of Y addition on the long time oxidation behaviors of high Nb containing TiAl alloys at 900 °C

Synergistic effect of Y and Nb on the high temperature oxidation resistance of high Nb containing TiAl alloys

“…As a result, the Tie45Ale9Nb alloy with 0.2 at.% of Y addition has the best oxidant resistance performance while the Tie45Ale6Nb alloy with 0.4 at.% Y displays a relatively good oxidation resistance ability. And previous researches also showed that 0.3 at.% Y was the proper content on Tie45Ale8Nb alloy [11]. Taken altogether, it can be concluded that the optimum amount of Y decreases with an increase of Nb and the principle of Y addition is choosing the minimum amount on the premise of meeting enough spallation resistance.…”

“…6 reveal that rutile TiO 2 crystalline (marked 'A') is surrounded by dense and fine Al 2 O 3 particles (marked 'B'). In our previous study, L. L. Zhao et al found that there is Y-rich phase in the spherical-shaped particles [11]. With more addition of Y, the amount of spherical-shaped particles increase and the oxides are refined, as shown in Fig.…”

“…Studies have shown that high Nb containing TiAl alloys with a proper amount of Y performed outstanding long-term oxidation resistance because of the strengthened spallation resistance of scale [9e15]. In our previous work, we found that 0.3 at.% Y addition could enhance the adherence of oxide scale on Tie45Ale8Nb alloys while guarantee low oxidation rate [11]. And Tie45Ale7Nb alloy with 0.4 at.% Y possessed the most excellent long-term high temperature oxidation resistance [13].…”

Effect of Nb on oxidation behavior of high Nb containing TiAl alloys

“…The element distribution maps detected by EDS of the cross-section of the oxide scale show that Al is enriched in the black area and Ti distributes in the grey area. XRD and EDS analysis [17] indicated that the scale structure of Ti-45Al-8Nb is in order of TiO 2 layer/Al 2 O 3 layer/(Ti,Nb)O 2 -rich layer/Nbrich layer from outside which is similar to it formed in the early stage. Fig.…”

A closely-complete peritectic transformation during directional solidification of a Ti-45Al-8.5Nb alloy

“…Niobium-rich g-TiAl-based alloys are potential candidates for high-temperature structural applications because of their excellent mechanical behaviour and good oxidation resistance at elevated temperatures [1,2]. However, their applications are mainly hindered by the poor ductility and toughness at room temperature (RT) [3].…”