| Site Occupation of Nb in gamma-TiAl: Beyond the Point Defect Gas Approximation | |
| Diao, Wei1,2; Ye, Li-Hua1; Ji, Zong-Wei1,3; Yang, Rui1; Hu, Qing-Miao1 | |
| Corresponding Author | Hu, Qing-Miao(qmhu@imr.ac.cn) |
| 2019-12-01 | |
| Source Publication | ACTA METALLURGICA SINICA-ENGLISH LETTERS
 |
| ISSN | 1006-7191 |
| Volume | 32Issue:12Pages:1511-1520 |
| Abstract | Microalloying is an effective approach to improve the mechanical properties of gamma -TiAl intermetallic compound. Knowledge about the site occupancy of the ternary alloying element in the crystal lattice of gamma -TiAl is highly demanded in order to understand the physics underlying the alloying effect. Previous first-principle methods-based thermodynamic models for the determination of the site occupancy were based on the point defect gas approximation with the interaction between the point defects neglected. In the present work, we include the point defect interaction energy in the thermodynamic model, which allows us to predict the site occupancy of the ternary alloying element in gamma -TiAl beyond the point defect gas approximation. The model is applied to the gamma -TiAl-Nb alloy. We show that, at low temperature, the site occupancy of Nb atoms depends on the composition of the alloy: Nb atoms occupy the Al sublattice for the Ti-rich alloy but occupy Ti sublattice for the Al-rich alloy. The fraction of Nb atoms occupying Al sublattice in the Ti-rich alloy decreases drastically, whereas the fraction of Nb atoms on the Ti sublattice in the Al-rich alloy decreases slightly with increasing temperature. At high temperature, Nb atoms occupy dominantly the Ti sublattice for both the Ti-rich and Al-rich alloys. The interaction between the point defects makes the Ti sublattice more favorable for the Nb atoms to occupy. |
| Keyword | Site preference Titanium aluminides Special quasi-random structures First principles method |
| Funding Organization | National Key Research and Development Program of China ; National Natural Science Foundation of China |
| DOI | 10.1007/s40195-019-00925-z |
| Indexed By | SCI |
| Language | 英语 |
| Funding Project | National Key Research and Development Program of China[2016YFB0701301] ; National Natural Science Foundation of China[91860107] |
| WOS Research Area | Metallurgy & Metallurgical Engineering |
| WOS Subject | Metallurgy & Metallurgical Engineering |
| WOS ID | WOS:000495116000008 |
| Publisher | CHINESE ACAD SCIENCES, INST METAL RESEARCH |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/137031 |
| Collection | 中国科学院金属研究所 |
| Corresponding Author | Hu, Qing-Miao |
| Affiliation | 1.Chinese Acad Sci, Inst Met Res, Wenhua Rd 72, Shenyang 110016, Liaoning, Peoples R China 2.Univ Sci & Technol China, Sch Mat Sci & Engn, Jinzhai Rd 96, Hefei 230026, Anhui, Peoples R China 3.Univ Chinese Acad Sci, Yuquan Rd 19A, Beijing 100049, Peoples R China |
| Recommended Citation GB/T 7714 | Diao, Wei,Ye, Li-Hua,Ji, Zong-Wei,et al. Site Occupation of Nb in gamma-TiAl: Beyond the Point Defect Gas Approximation[J]. ACTA METALLURGICA SINICA-ENGLISH LETTERS,2019,32(12):1511-1520. |
| APA | Diao, Wei,Ye, Li-Hua,Ji, Zong-Wei,Yang, Rui,&Hu, Qing-Miao.(2019).Site Occupation of Nb in gamma-TiAl: Beyond the Point Defect Gas Approximation.ACTA METALLURGICA SINICA-ENGLISH LETTERS,32(12),1511-1520. |
| MLA | Diao, Wei,et al."Site Occupation of Nb in gamma-TiAl: Beyond the Point Defect Gas Approximation".ACTA METALLURGICA SINICA-ENGLISH LETTERS 32.12(2019):1511-1520. |
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