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| 凝固模式对定向凝固TiAl-Nb合金组织和力学性能影响 |
| Effects of Solidification Modes on Microstructure and Mechanical Properties of Directionally Solidified TiAl-Nb Alloys |
| Received:April 08, 2018 Revised:May 10, 2018 |
| DOI：10.3969/j.issn.1674-6457.2018.03.002 |
| 中文关键词: 钛铝铌合金 定向凝固 显微组织 力学性能 |
| 英文关键词: TiAl-Nb alloys directional solidification microstructure mechanical properties |
| 基金项目:国家自然科学基金（51671026） |
| Author Name | Affiliation | | LI Yan | 1. Cast Titanium Alloys Research Center, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
2. Beijing Engineering Research Center of Advanced Titanium Alloy Precision Forming Technology, Beijing 100095, China | | WANG Tian-hao | State Key Laboratory for Advance Metal and Materials, University of Science and Technology Beijing, Beijing 100083, China | | ZHANG Li-wei | State Key Laboratory for Advance Metal and Materials, University of Science and Technology Beijing, Beijing 100083, China | | LIN Jun-pin | State Key Laboratory for Advance Metal and Materials, University of Science and Technology Beijing, Beijing 100083, China | | DING Xian-fei | 1. Cast Titanium Alloys Research Center, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
2. Beijing Engineering Research Center of Advanced Titanium Alloy Precision Forming Technology, Beijing 100095, China | | LI Jian-chong | 1. Cast Titanium Alloys Research Center, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
2. Beijing Engineering Research Center of Advanced Titanium Alloy Precision Forming Technology, Beijing 100095, China | | NAN Hai | 1. Cast Titanium Alloys Research Center, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China
2. Beijing Engineering Research Center of Advanced Titanium Alloy Precision Forming Technology, Beijing 100095, China |
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| 中文摘要: |
| 目的 研究凝固模式对TiAl-Nb合金定向凝固组织和力学性能的影响。方法 利用Bridgman定向凝固方法制备了单一β、亚包晶、过包晶以及单一α相4种凝固模式的TiAl-Nb合金，对显微组织进行观察，并进行室、高温拉伸性能测试及断口形貌分析。结果 单一β凝固模式柱状晶明显倾斜，其他凝固模式合金的柱状晶挺直且宽度较均匀，除单一α凝固合金中片层方向近似与定向凝固方向平行外，其他模式凝固合金中大部分片层方向与定向凝固方向呈近45°夹角；拉伸性能结果显示，亚包晶合金室温和高温抗拉强度最高，分别为429和483 MPa，单一α相合金室温和高温抗拉强度最小，分别为281和204 MPa。结论 亚包晶合金其室温和高温拉伸性能均高于其他凝固模式的合金性能，但定向凝固试样制备过程中产生Y2O3颗粒夹杂，导致拉伸试验过程容易形成应力集中，致使定向凝固TiAl-Nb合金较早发生断裂。 |
| 英文摘要: |
| The paper aims to study influences of solidification modes on directional solidification structure and mechanical property of TiAl-Nb alloy. Different solidification modes in TiAl-8Nb alloys including single β-phase, hypo-peritectic, hyper-peritectic and single α-phase, were prepared by Bridgman directional solidification technique. Microstructure of directional solidified alloy were observed. Mechanical properties of the alloys at room/high temperature were measured with analysis of fracture morphology. The columnar grain was obviously tilted in single β-phase solidification mode, but that was straight and uniform in other solidification modes. The lamellar orientation in single-α mode was mostly parallel to the growth direction, but that in other modes were approximately angled with 45º to the growth direction. Tensile properties show that tensile strength of the hypo-peritectic alloys at room/high temperature were the best, and respectively reached 429 and 483 MPa; tensile strength of single α-phase alloys at room/high temperature were the lowest, and respectively reached 281 and 204 MPa. The tensile properties of TiAl-Nb at room/high temperature were higher than those of other solidification modes, but Y2O3 particles were produced in the process of directional solidification, leading to stress concentration during tensile test process and advanced fracture for directionally solidified TiAl-Nb alloy at room temperature. |
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