Influence of oxygen on solidification behaviour of cast TiAl-based alloys
- 作者：J. Zollinger ; J. Lapin ; D. Daloz ; H. Combeau
- 关键词：A. Titanium aluminides ; based on TiAl ; B. Phase transformations ; C. Casting ; D. Microstructure
- 刊名：Intermetallics
- 出版年：2007
- 期刊代码：36_09669795
- 类别：ms
- 出版时间：October 2007
- 卷：15
- 期：10
- 页码：1343-1350
- 文件大小：1712 K
摘要
The influence of oxygen on solidification behaviour of cast TiAl-based alloys containing 40–48 at.%of Al was studied. Twelve alloys with fixed Ti:Al ratios ranging from 1.08 to 1.5 and oxygen content of 0.1, 0.8 and 1.5 at.%were prepared by induction melting and casting in a cold crucible under protective atmosphere. Increasing oxygen content affects significantly the macrostructure of the as-cast ingots, increases volume fraction of the α phase formed during peritectic solidification and leads to a change of the β primary solidification phase to the α phase in ternary Ti–44.2Al–1.4O, Ti–47.3Al–0.9O and Ti–47.2Al–1.5O (at.%) alloys. In the case of the alloy with the α primary solidification phase, the partition coefficients achieve values of 
and 
. In alloys containing 1.5 at.%of oxygen, it has been observed that the β/α solidification phase transition is shifted to a lower aluminium contents when compared to that of binary systems. Oxygen extends the stability of single α phase region.