Phase equilibria in the Ti-Al-O system at 945 C and analysis of Ti/Al{sub 2}O{sub 3} reactions
- Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering
Phase relations in the Ti-Al-O system were evaluated experimentally at 945 C. The tie lines were established using equilibrated samples with phase compositions determined by electron probe microanalysis. The phase relations were in agreement with previous estimates but the phase fields of {alpha}-Ti[O,Al] and Ti{sub 3}Al[O] were significantly different. The Ti{sub 3}Al[O] phase has a maximum solubility of 22 at.% O, corresponding to a nominal stoichiometry of Ti{sub 3}AlO, whereas the {alpha}-Ti[O,Al] phase, at a maximum O solubility of 33.33 at.%, has a negligible amount of Al in solution. The disagreement between these results and previous studies was attributed to the differences in experimental techniques for sample preparation and analysis. The reported layer sequences at the Ti/Al{sub 2}O{sub 3} interface were evaluated based on the ternary section and the corresponding O activity diagram. The layered interfaces were found to be stable, with the evolution of the reaction products governed by the thickness of the initial Ti layer and the partial pressure in the ambient.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 79767
- Journal Information:
- Journal of the American Ceramic Society, Vol. 78, Issue 3; Other Information: PBD: Mar 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Formation of Z-Ti{sub 50}Al{sub 30}O{sub 20} in the sub-oxide zones of {gamma}-TiAl-based alloys during oxidation at 1000 C
Crystallization and (Al,Ti)-oxide growth in annealed TiO{sub 2}-Al{sub 2}O{sub 3} multilayers