Growth Directions of Primary Phases in Directionally Solidified Ti-45Al-7Nb Alloys
| Autor: | Yan Jie, Zheng Lijing, Zhang HuaRui, Xiao Zhixia, Zhang Hu |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | High Temperature Materials and Processes, Vol 32, Iss 1, Pp 69-75 (2013) |
| Druh dokumentu: | article |
| ISSN: | 0334-6455 2191-0324 |
| DOI: | 10.1515/htmp-2012-0061 |
| Popis: | Ti-45Al-7Nb alloys are produced by liquid-metal-cooling (LMC) directional solidification (DS) furnace with different temperature gradients (G) at a range of 40–80 K/cm. The growth directions of primary β phases and the deflection angles relative to the 〈100〉β direction were investigated. The solidification pathway of alloy is: Liq. → Liq. + β → β → β + α → α + γ → lamella (α2 + γ) + B2. Primary dendrite arm spacing λ reduced from 611.4 µm to 508.7 µm when G increased from 40 K cm−1 to 80 K cm−1. Grains with lamellar orientation aligned at the angles of 12–15° and 55° to growth direction were favored for various G. The orientations of the γ lamellas in steady-state regions were identified by the electron backscattered diffraction analysis (EBSD). The results indicated that the growth directions of primary bcc-β dendrites were 〈211〉β and 〈110〉β at 40 K/cm, 〈210〉β and 〈211〉β at 50 K/cm and 〈211〉β at 80 K/cm, the deflection angle of 〈211〉β relative to 〈100〉β direction is 35.3°. |
| Databáze: | Directory of Open Access Journals |
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