全部 标题 作者
关键词 摘要

OALib Journal期刊
ISSN: 2333-9721
费用:99美元

查看量下载量

相关文章

更多...
材料工程  2013 

热处理对定向凝固Nb-Ti-Si基超高温合金组织及显微硬度的影响

DOI: 10.3969/j.issn.1001-4381.2013.06.002, PP. 5-11

Keywords: 均匀化热处理,Nb-Ti-Si基超高温合金,组织演变,定向凝固,显微硬度

Full-Text   Cite this paper   Add to My Lib

Abstract:

对以2.5μm/s和50μm/s抽拉速率定向凝固的Nb-Ti-Si基超高温合金试样,分别进行了在1250,1350℃和1400℃保温50h的均匀化热处理。结果表明均匀化热处理后的组织主要由Nbss,β(Nb,X)5Si3及γ(Nb,X)5Si3相组成,在以2.5μm/s抽拉速率定向凝固的试样中还出现了针状Cr2(Nb,Ti)析出相。随均匀化热处理温度的升高,针状析出相的数量增多;经均匀化热处理后定向凝固试样中的大块六边形硅化物的平直边界和尖锐的棱角逐渐圆润;共晶胞中心的细小硅化物逐渐球化,而共晶胞内板条状的硅化物部分碎化,逐渐变成小岛状。热处理后并没有发生β(Nb,X)5Si3向α(Nb,X)5Si3的晶型转变。同定向凝固态相比较,均匀化热处理后合金的显微硬度显著提高,并且随着均匀化热处理温度的升高,合金及各相的显微硬度先升高后降低,在1350℃/50h热处理后显微硬度值最高。

References

[1]  GUO X P, GAO L M, GUAN P. Microstructure and mechanical properties of an advanced niobium based ultrahigh temperature alloy [J]. Materials Science Forum,2007,539-543:3690-3695.
[2]  GUO H S, GUO X P. Microstructure evolution and room temperature fracture toughness of an integrally directionally solidified Nb-Ti-Si based ultrahigh temperature alloy [J]. Scripta Materialia, 2011, 64(7): 637-640.
[3]  CHAN K S, DAVIDSON D L. Improving the fracture toughness of constituent phases and Nb-based in-situ composites by a computational alloy design approach [J]. Metallurgical and Materials Transactions A, 2003, 34(9): 1833-1849.
[4]  TEWARI R, SONG H, DEY G K, et al. Microstructural evolution in niobium based alloys [J]. Metallurgical and Materials Transactions A, 2008, 39(7): 1506-1518.
[5]  BEWLAY B P, JACKSON M R, ZHAO J C, et al. A review of very-high temperature Nb-silicide-based composites [J]. Metallurgical and Materials Transactions A, 2003, 34(10): 2043-2052.
[6]  BEWLAY B P, JACKSON M R, LIPSITT H A. The balance of mechanical and environmental properties of a multielement niobium-niobium silicide-based in situ composite [J]. Metallurgical and Materials Transactions A, 1996, 27(12): 3801-3808.
[7]  ZELENITSAS K, TSAKIROPOULOS P. Study of the role of Al and Cr additions in the microstructure of Nb-Ti-Si in situ compositions [J]. Intermetallics, 2005, 13(10): 1079-1095.
[8]  VENKATRAMAN M, NEUMANN J P. The Cr-Nb (chromium-niobium) system [J]. Journal of Phase Equilibria, 1986, 7(5): 462-466.
[9]  OKAMOTO H. Cr-Si (chromium-silicon) [J]. Journal of Phase Equilibria, 1997, 18(2): 222.
[10]  SHA J B, HIRAI H, TABARU T, et al. Mechanical properties of as-cast and directionally solidified Nb-Mo-W-Ti-Si in-situ composites at high temperatures [J]. Metallurgical and Materials Transactions A, 2003, 34(1): 85-94.
[11]  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.JIA Li-na, GUO Xi-ping. Effects of alloying elements and heat treatments on the microstructure and mechanical properties of refractory metal silicide-based alloys [J]. Rare Metal Materials and Engineering, 2007, 36(7): 1304-1308.
[12]  GUO H S, GUO X P. Microstructure and microhardness of directionally solidified and heat-treated Nb-Ti-Si based ultrahigh temperature alloy [J]. Transactions of Nonferrous Metals Society of China, 2011, 21(6): 1283-1290.
[13]  MENDIRATTA M G, DIMIDUK D M. Phase relations and transformation kinetics in the high Nb region of the Nb-Si system [J]. Scripta Metallurgica, 1991, 25(1): 237-242.
[14]  王勇, 郭喜平, 张超峰,等. 电弧熔炼Nb-Ti-Si合金的组织和室温力学性能[J].特种铸造及有色合金, 2010, 30(6): 556-561. WANG Yong, GUO Xi-ping, ZHANG Chao-feng, et al. Microstructure and ambient mechanical properties of Nb-Ti-Si based alloy prepared by consumable arc melting [J]. Special Casting and Nonferrous Alloys, 2010, 30(6): 556-561.
[15]  ZELENITSAS K, TSAKIROPOULOS P. Effect of Al, Cr and Ta additions on the oxidation behaviour of Nb-Ti-Si in situ composites at 800℃ [J]. Materials Science and Engineering A, 2006, 416(1-2): 269-280.
[16]  TEWARI R, SONG H K, VASUDEVAN V K, et al. Microstructural characterization of multicomponent Nb-Ti-Si-Cr-Al-X alloys [J]. Metallurgical and Materials Transactions A, 2006, 37(9): 2669-2682.
[17]  MURRAY J L. The Cr-Ti (chromium-titanium) system [J]. Journal of Phase Equilibria, 1981, 2(2): 174-181.

Full-Text

Contact Us

service@oalib.com

QQ:3279437679

WhatsApp +8615387084133