Influence of Oxygen on the Solidification Behavior of High-Nb TiAl Alloys

摘要

The influence of oxygen on the solidification behavior of an as-cast TiAl-based alloy has been studied. Alloys with composition of Ti-49Al-10Nb (in at, %) were prepared by non-consumable vacuum arc remelting. Each of the alloys was melted with an oxygen content around 0. 1,0. 8 and 1. 5 at. %. It's observed that the microstructure modification added by Nb can be removed when increase oxygen content. And the presence of the remarkable amount of α2 phase indicates that in high Nb-TiAl alloys, the primary solidification phase can also be turned from β to α due to the α stabilizing effect of oxygen. But when continuously increasing the oxygen content, the α2 phase content decreases. The proportion of α2 phase shows a tendency of first increase and then decrease with the increasing oxygen content.