| DD6单晶高温合金初熔组织演变机制研究 |
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| 引用本文： | 韩梅,岳晓岱,董建民,谢洪吉,李嘉荣.DD6单晶高温合金初熔组织演变机制研究[J].失效分析与预防,2019,14(3):166-171. |
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| 作者姓名： | 韩梅 岳晓岱 董建民 谢洪吉 李嘉荣 |
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| 作者单位： | 北京航空材料研究院先进高温结构材料重点实验室,北京,100095;北京航空材料研究院先进高温结构材料重点实验室,北京,100095;北京航空材料研究院先进高温结构材料重点实验室,北京,100095;北京航空材料研究院先进高温结构材料重点实验室,北京,100095;北京航空材料研究院先进高温结构材料重点实验室,北京,100095 |
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| 基金项目： | 国家重点研发计划专项项目 |
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| 摘 要： | 分析第二代单晶高温合金DD6在略高于固溶热处理窗口的温度1330℃下保温的初熔组织演变。结果表明:保温0.5h后,枝晶间发生明显初熔,并大量形成典型初熔组织,部分初熔组织中心形成显微孔洞;随保温时间延长,初熔逐渐消退并演变为正常合金组织;保温8h后,初熔组织完全消失,仅留下初熔形成的微孔。应用热力学、动力学计算分析试验结果可知:DD6合金在铸态下枝晶偏析显著,枝晶间固相线温度明显低于枝晶干,在略高于枝晶间固相线的温度下保温,初始阶段枝晶间发生初熔;继续保温,元素均匀化程度改善,枝晶间固相线温度升高,初熔组织逐渐消退,最终演变为正常合金组织。
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| 关 键 词： | ]DD6 单晶高温合金 热处理 初熔 微孔 |
| 收稿时间： | 2019-03-15 |
Evolutionary Mechanism of Incipient Melting Microstructure of Single Crystal Superalloy DD6 |
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| HAN Mei,YUE Xiao-dai,DONG Jian-min,XIE Hong-ji,LI Jia-rong.Evolutionary Mechanism of Incipient Melting Microstructure of Single Crystal Superalloy DD6[J].Failure Analysis and Prevention,2019,14(3):166-171. |
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| Authors: | HAN Mei YUE Xiao-dai DONG Jian-min XIE Hong-ji LI Jia-rong |
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| Affiliation: | (Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,China) |
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| Abstract: | The evolution of the incipient melting microstructure of the second-generation single crystal superalloy DD6 was studied during heat treatment at 1 330 ℃, slightly higher than its solution heat treatment window. After heat treated for 0.5 h, incipient melting occurs at interdendrites, and some of the incipient melting regions have a pore at the center; with the holding time increasing, incipient melting microstructure fades away gradually and totally disappears after 8 h. The experimental results are analyzed by thermodynamic and kinetic calculations. The solidus temperature of the interdendrite region of as-casting DD6 single crystal superalloy is apparently lower than that of the dendrite arm region because of severe dendrite segregation. During the heat treatment at a temperature slightly higher than the solidus temperature, incipient melting occurs initially; it fades away gradually with the improvement of element homogenization degree, and finally turns to normal microstructure. |
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| Keywords: | DD6 single crystal superalloy heat treatment incipient melting pore |
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