|
|||||
|
|
Effects of substitutional impurity Au and Si atoms on antiphase boundary energies in Ti3Al: A first principles study |
|
| Authors: | Yuichiro Koizumi Masataka Mizuno Atsushi Sugihara Yoritoshi Minamino Yasuharu Shirai |
| Affiliation: | 1. Department of Adaptive Machine Systems , Osaka University , 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan koizumi@imr.tohoku.ac.jp;3. Division of Materials and Manufacturing Science , Osaka University , 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan;4. Center for Atomic and Molecular Technologies , Osaka University , Suita, Osaka 565-0871, Japan;5. Department of Adaptive Machine Systems , Osaka University , 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan;6. Department of Materials Science and Engineering , Kyoto University , Sakyo, Kyoto 606-8501, Japan |
| Abstract: | Effects of substitutional impurity atoms Au and Si on the energies of antiphase boundaries (APBs) on {1100} and (0001) planes in a Ti3Al intermetallic compound were examined using first principles calculations. Au additions reduce the energies of APBs on both {1100} and (0001) planes by up to more than 40%. The reduction tends to be more remarkable especially when the added Au atom has larger number of Al atoms on its second-nearest neighbor sites rather than on first-nearest neighbor ones. In addition, in the case of Si addition, a significant energy reduction was found only for APBs on (0001) planes, and no remarkable dependence of APB energies on the coordinating atoms was found even for APBs on (0001) planes. These results are crucial to both understanding of the effect of APBs on the impurity diffusivity and predicting the ability of impurity atoms to stabilize antiphase domain structure that increases the strength of Ti3Al dramatically. |
| Keywords: | antiphase boundary impurity segregation defect first-principles calculation intermetallic compound ordered intermetallic titanium aluminide |