Effect of Solute Redistribution on Seeding Process of TiAl Alloys with Limited Convection in a Float Zone
Two different analytic models, in which convection in the float zone is assumed, are developed to understand the solute redistributions during general seeding and quasi-seeding processes of TiAl alloys, respectively. The results suggest that the solute redistribution plays an important effect in the...
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| Format: | Article |
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MDPI AG
2021-09-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/11/10/1525 |
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| author | Yi-Long Xiong Jun Shen Yu-Jun Du |
| author_facet | Yi-Long Xiong Jun Shen Yu-Jun Du |
| author_sort | Yi-Long Xiong |
| collection | DOAJ |
| description | Two different analytic models, in which convection in the float zone is assumed, are developed to understand the solute redistributions during general seeding and quasi-seeding processes of TiAl alloys, respectively. The results suggest that the solute redistribution plays an important effect in the phase selection and microstructural development during the initial stage of seeding processes. In the initial stage of the quasi-seeding process, the interface concentration increases gradually and the solute diffusion boundary forms with the crystal growth of α phase. Correspondingly, a maximum constitutional undercooling with respect to β phase occurs ahead of the solidifying α interface and then decreases gradually. Simultaneously, the position where the maximum constitutional undercooling occurs also moves forward with regard to the interface. While in the initial stage of the general seeding process, the α phase can grow continuously as stable phase when the initial composition of the melt is higher than Al 48.9%. Under the influence of both the constitutional undercooling and Ti<sub>5</sub>Si<sub>3</sub> particles, coarse dendrites form and then are transformed to cellular morphology. Nevertheless, the lamellar microstructure can still be aligned well during the entire seeding process. Besides, it is also found that the thickness of solute diffusion boundary decreases with the increase of convection intensity and thus, the growing interface become more stably correspondingly, which is beneficial to the lamellar alignment of TiAl alloys. |
| first_indexed | 2024-03-10T06:23:27Z |
| format | Article |
| id | doaj.art-d61e547149374d17baca3db94e7d6082 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T06:23:27Z |
| publishDate | 2021-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-d61e547149374d17baca3db94e7d60822023-11-22T19:08:10ZengMDPI AGMetals2075-47012021-09-011110152510.3390/met11101525Effect of Solute Redistribution on Seeding Process of TiAl Alloys with Limited Convection in a Float ZoneYi-Long Xiong0Jun Shen1Yu-Jun Du2Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, ChinaKey Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, ChinaKey Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, ChinaTwo different analytic models, in which convection in the float zone is assumed, are developed to understand the solute redistributions during general seeding and quasi-seeding processes of TiAl alloys, respectively. The results suggest that the solute redistribution plays an important effect in the phase selection and microstructural development during the initial stage of seeding processes. In the initial stage of the quasi-seeding process, the interface concentration increases gradually and the solute diffusion boundary forms with the crystal growth of α phase. Correspondingly, a maximum constitutional undercooling with respect to β phase occurs ahead of the solidifying α interface and then decreases gradually. Simultaneously, the position where the maximum constitutional undercooling occurs also moves forward with regard to the interface. While in the initial stage of the general seeding process, the α phase can grow continuously as stable phase when the initial composition of the melt is higher than Al 48.9%. Under the influence of both the constitutional undercooling and Ti<sub>5</sub>Si<sub>3</sub> particles, coarse dendrites form and then are transformed to cellular morphology. Nevertheless, the lamellar microstructure can still be aligned well during the entire seeding process. Besides, it is also found that the thickness of solute diffusion boundary decreases with the increase of convection intensity and thus, the growing interface become more stably correspondingly, which is beneficial to the lamellar alignment of TiAl alloys.https://www.mdpi.com/2075-4701/11/10/1525TiAl alloysdirectional solidificationmicrostructural developmentseed crystalssolute redistribution |
| spellingShingle | Yi-Long Xiong Jun Shen Yu-Jun Du Effect of Solute Redistribution on Seeding Process of TiAl Alloys with Limited Convection in a Float Zone Metals TiAl alloys directional solidification microstructural development seed crystals solute redistribution |
| title | Effect of Solute Redistribution on Seeding Process of TiAl Alloys with Limited Convection in a Float Zone |
| title_full | Effect of Solute Redistribution on Seeding Process of TiAl Alloys with Limited Convection in a Float Zone |
| title_fullStr | Effect of Solute Redistribution on Seeding Process of TiAl Alloys with Limited Convection in a Float Zone |
| title_full_unstemmed | Effect of Solute Redistribution on Seeding Process of TiAl Alloys with Limited Convection in a Float Zone |
| title_short | Effect of Solute Redistribution on Seeding Process of TiAl Alloys with Limited Convection in a Float Zone |
| title_sort | effect of solute redistribution on seeding process of tial alloys with limited convection in a float zone |
| topic | TiAl alloys directional solidification microstructural development seed crystals solute redistribution |
| url | https://www.mdpi.com/2075-4701/11/10/1525 |
| work_keys_str_mv | AT yilongxiong effectofsoluteredistributiononseedingprocessoftialalloyswithlimitedconvectioninafloatzone AT junshen effectofsoluteredistributiononseedingprocessoftialalloyswithlimitedconvectioninafloatzone AT yujundu effectofsoluteredistributiononseedingprocessoftialalloyswithlimitedconvectioninafloatzone |