Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5457713 | Intermetallics | 2017 | 7 Pages |
Abstract
The precipitation of γ phase and heterogeneous nucleation of Ïo phase within βo phase areas are common phenomena in TiAl alloys. However, detailed explanation on the corresponding phase transformation mechanisms is still lacking. In this study, the precipitation behaviors of γ and Ïo phases in a quenched Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y alloy are investigated. The results show that large γ grains form after quenching whereas small γ particles can directly nucleate within the remaining βo phase during annealing. Semi-coherent interfaces are observed between γ and βo phases and the average distance between dislocations is evaluated. The heterogeneous nucleation of Ïo phase at the lamellar colony boundary is imaged by HRTEM. Edge-to-edge method is used to calculate the orientation relationship between γ and Ïo phases. The γ phase grows up faster than Ïo phase within the βo phase areas during annealing at 800 °C.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Lin Song, Xingguo Hu, Tiebang Zhang, Jinshan Li,