采用氧化钇坩埚真空感应熔炼方法制备了Nb-16Si-22Ti-6Hf和Nb-16Si-22Ti-6Hf-2Cr-2Al合金铸锭,并在1500℃时进行了100 h的热处理。结果表明,铸态和热处理后的合金均由铌基固溶体（NbSS）、Nb3Si、β-Nb5Si3和γ-Nb5Si3组成。冷却速度、合金化元素及热处理均会影响合金的组织。冷却速度较低时,铸锭顶部的组织较粗大;合金化元素Cr和Al可以促进Nb3Si的共析转变,使合金铸锭的组织均匀、细化;热处理则促进Nb3Si→Nb5Si3＋NbSS的发生,且Nb3Si的尺寸和体积分数均减小,边界变圆润,NbSS枝晶粗化,共晶组织由片层状变为不规则岛状。
Nb-16Si-22Ti-6Hf（-2Cr-2Al） alloys were prepared using vacuum induction melting in Y2O3 crucible,and the heat treatment was conducted at 1500℃ for 100h.The constituent phases analysis show that the ingots are composed of the phases of Nb solid solution（NbSS）、 Nb3Si、 β-Nb5Si3 and γ-Nb5Si3.The cooling rate,alloying elements and heat treatment have effects on the microstructures of the ingots.The lower the cooling rate is,the coarser the microstructures at the top of the ingots are.The addition of Cr and Al promotes the eutectoid reaction,resulting in the much more homogenous and finer of the microstructures.While the heat treatment promotes the eutectoid reaction of Nb3Si→Nb5Si3＋NbSS,leading to the decrease in the dimension and the volume fraction of Nb3Si,and the smooth of the boundary.Furthermore,the NbSS dendrites coarsen slightly,and the lamellar-like eutectic structures change into irregular island-like during the heat treatment.
参考文献
| [1] | Bewlay B P, Jackson M R, Zhao J C, Subramanian P R. A review of very- high - temperature Nb - silicide - based composites [J ]. Metallurgical and Materials Transactions, 2003, 34(10): 2043-2052. |
| [2] | 刘肖,李玉龙,沙江波,马朝利.合金元素对Nb-Mo-Si合金相平衡及Nb-Nb5Si3共晶组织形态的影响[J].复合材料学报,2008,25(2):16-20. |
| [3] | 孙志平,郭喜平.合金化对铌基固溶体合金和铌硅化物基合金室温断裂韧性影响的研究进展[J].材料导报,2008,22(4):79-83. |
| [4] | 田晓东,郭喜平.铌基超高温合金表面Si-Al包埋共渗抗氧化涂层的组织形成[J].中国有色金属学报,2008,18(1):7-12. |
| [5] | 贾丽娜,郭喜平.合金化和热处理对难熔金属硅化物基合金组织和性能影响的研究现状[J].稀有金属材料与工程,2007,36(7):1304-1308. |
| [6] | 何永胜,郭喜平,孙志平,巨小创.铌硅化物基超高温合金电弧熔炼态组织和成分分布[J].材料工程,2009(1):4-9. |
| [7] | Geng J, Tsakiropoulos P. A study of microstructure and oxidation of Nb - Si - Cr - Al - Mo in situ composites alloyed with Ti, Hf, Sn [J]. Intermetallics, 2007, 15(3): 382-395. |
| [8] | Zelenitsas K, Tsakiropoulos P. Study of the role of Al and Cr additions in the microstructure of Nb - Ti - Si in situ composites [J]. Intermetallics, 2005, 13(10): 1079-1095. |
| [9] | 宋立国,曲士昱,宋尽霞.1250℃热处理对Nb-16Si-24Ti-6Cr-6Al-2Hf合金的组织影响[J].材料工程,2005(12):30-36. |
| [10] | 郭海生,郭喜平.高温均匀化及时效处理对Nb-Ti-Si基超高温合金组织的影响[J].稀有金属材料与工程,2008,37(9):1601-1605. |
| [11] | 贾丽娜,郭喜平.热处理对铌硅基共晶自生复合材料组织的影响[J].稀有金属材料与工程,2008,37(5):878-882. |
| [12] | Bewlay B P, Jackson M R, Zhao J C, Subramanian P R, Mendiratta M G, Lewandowski J J. Ultrahigh-temperature Nb- silicide- based composites [J]. Mrs Bulletin, 2003, 28 (9) : 646-653. |
| [13] | Bewlay B P, Jackson M R, Subramanian P R. Processing high- temperature refractory- metal silicide in- situ composites [J]. JOM Journal of the Minerals, Metals and Materials Society, 1999, 51(4): 32-36. |
| [14] | Li X J, Chen H F, Sha J B, Zhang H. The effects of melting technologies on the microstructures and properties of Nb -16Si - 22Ti - 2Al - 2Hf - 17Cr alloy [J]. Materials Science and Engineering A, 2010, 527(23): 6140-6162. |
| [15] | 李伟.NB-Si系金属硅化物的组织形貌和力学性能研究[D].上海:上海交通大学,2005. |
| [16] | Sekido Nobuaki, Kimura Yoshisato, Wei Fu- Gao, Miura Seiji, Mishima Yoshinao. Effect of lamellar spacing on the mechanical properties of (Nb)/(Nb, Ti)5Si3 two-phase alloys [J]. J Japan Inst Metals, 2000, 64(11): 1056-1061. |
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