Influencing factors and control methods of surface microstructure transformation of single crystal blade
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摘要:
针对单晶叶片铸件在高温热处理后,极易在结构畸变区域发生结构再结晶问题,本研究提出了一种基于单晶再结晶临界应力特性的叶片结构残余应力控制方法,旨在通过研究单晶合金再结晶的临界应力特性,并结合结构细节优化设计方法,将叶片结构残余应力水平控制在单晶再结晶临界应力的安全区域内。结果表明:诱发单晶叶片结构再结晶的两大因素是温度和应力集中水平,再结晶起源于不连续的胞状组织,且发生单晶再结晶时的临界应力与叶片结构设计参数、热处理温度之间存在一定的函数关系,经真实叶片试验验证,证实该方法可实现单晶叶片结构完整性与表层组织连续性的控制,有效抑制单晶叶片表层组织的转变。
Abstract:The problem of surface recrystallization was found on the structural distortion region of single crystal blade after the high temperature heat treating. To solve this problem, a method was proposed based on critical stress of recrystallization and residual stress of structure. With the help of structural optimization technology, the study showed that the critical stress happened justly under the recrystallization of the single crystal blade, and the residual stress level of structure was no more than the critical stress of recrystallization stress. Results showed that the temperature and stress concentration level were two major factors inducing structural recrystallization, and the recrystallization was originated from discontinuous cellular microstructure of the single crystal blade. Meanwhile, the critical stress of recrystallization was used to establish a relationship with the structure design parameters and the heat treatment temperature, then, the test validation work was completed for the real blade. This method is effective to restrain the structural recrystallization of single crystal blade and control the structural integrity and surface microstructure continuity.
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表 1 实验结果对比分析
Table 1. Comparative analysis of experimental results
分类 编号 载荷F/N 热处理参数 实验结果 温度/℃ 时间/h Ⅰ 1 1000 1100 2.5 γ 和 γ′相未见异常。 2 1000 1150 2.5 不连续的胞状组织。 3 1000 1200 2.5 大量胞状组织,部分枝晶杆区出现不连续分布的晶粒。 4 1000 1250 2.5 晶粒明显长大,开始聚集。 Ⅱ 7 750 1150 2.5 γ 和 γ′相未见异常。 8 750 1200 2.5 不连续的胞状组织。 9 750 1250 2.5 大量胞状组织,部分枝晶杆区域出现不连续分布的再结晶晶粒,
数量少,分布零星,晶粒彼此分隔。Ⅲ 13 500 1200 2.5 γ 和 γ′相未见异常。 14 500 1250 2.5 γ′ 相溶解,枝晶杆区域出现少量不连续的胞状结构。 -
[1] 赵新宝. 高梯度定向凝固单晶高温合金晶体取向研究[D]. 西安: 西北工业大学, 2010.ZHAO Xinbao. Crystal orientation of single crystal superalloys under high thermal gradient directional solidification[D]. Xi’an: Northwest Polytechnic University, 2010. (in Chinese) [2] 陶春虎,张卫方,李运菊,等. 定向凝固和单晶高温合金的再结晶[J]. 失效分析与预防,2006,1(4): 1-7. doi: 10.3969/j.issn.1673-6214.2006.04.001TAO Chunhu,ZHANG Weifang,LI Yunju,et al. Recrystallization of directionally solidified and single crystal superalloy[J]. Failure Analysis and Prevention,2006,1(4): 1-7. (in Chinese) doi: 10.3969/j.issn.1673-6214.2006.04.001 [3] GELL M, DU HL D N, GIAMEI A F. The development of single crystal superalloy turbine blades[R]. Warrendale, US: Pratt and Whitney Aircraft Group, 1980. [4] CORRIGAN J, VOGT R G, MIHALISIN J R, et al. Single crystal superalloy articles with reduced grain recrystallization: EP10/38982A1[P]. 2000-09-27. [5] COX D,ROEBUCK B. Recrystallization of single crystal super alloy CMSX24[J]. Materials Science and Technology,2003,19: 440-446. doi: 10.1179/026708303225010731 [6] PORTER A,RALPH B. Recrystallization of a nickel-base superalloy: kinetics and microstructural development[J]. Material Science Engine,1983,59: 69-78. doi: 10.1016/0025-5416(83)90089-7 [7] PORTER A,RALPH B. The recrystallization of nickel-base superalloys[J]. Journal of Materials Science,1981,16: 7072-7131. [8] TAKEO T,YOSHIHIRO T,TAKASHI M. Low stress creep of single crystals with [011] orientation[J]. Material Science Forum,2003,31: 803-808. [9] BOND S D,MARTIN J W. Surface recrystallization in a single crystal nickel based superalloy[J]. Journal of Materials Science,1984,19: 3867-3872. doi: 10.1007/BF00980749 [10] WANG D L, JIN T, YANG S Q, et al. Surface recrystallization and its effect on rupture life of SRR99 single crystal superalloy[J]. Materials Science Forum, 2007, 546/547/548/549: 1229-1234 [11] JO C Y,CHO H Y,KIM H M. Effect of recrystallization on microstructural evolution and mechanical properties of single crystal nickel base superalloy CMSX22[J]. Materials Science and Technology,2003,19: 1665-1670. doi: 10.1179/026708303225008301 [12] KHAN T,CARON P,NAKAGAWA Y G. Mechanical behavior and processing of DS and single crystal superalloy[J]. Journal of Metals Science,1986,38(7): 16-19. [13] 陈素玲,蒋文娟,杜娟. 镍基单晶高温合金表面再结晶控制技术的研究进展[J]. 重庆大学学报,2020,43(8): 74-78.CHEN Suling,JIANG Wenjuan,DU Juan. Research progress of surface-recrystallization control technology of Ni-based single-crystal super alloy[J]. Journal of Chongqing University,2020,43(8): 74-78. (in Chinese) [14] 卜昆,邱飞,王志红. 镍基单晶叶片制造技术及再结晶研究进展[J]. 航空制造技术,2016,21(8): 34-40. doi: 10.16080/j.issn1671-833x.2016.21.034BU Kun,QIU Fei,WANG Zhihong. Development of manufacture technology and recrystallization study for nickel based single crystal hollow turbine blade[J]. Aeronautical Manufacturing Technology,2016,21(8): 34-40. (in Chinese) doi: 10.16080/j.issn1671-833x.2016.21.034 [15] 卫平,李嘉荣,钟振纲. 一种镍基单晶高温合金的表面再结晶研究[J]. 材料工程,2001, 26(10): 5-8. doi: 10.3969/j.issn.1001-4381.2001.10.002WEI Ping,LI Jiarong,ZHONG Zhengang. Study on the surface recrystallization of a Ni-based single crystal superalloy[J]. Journal of Materials Engineering,2001, 26(10): 5-8. (in Chinese) doi: 10.3969/j.issn.1001-4381.2001.10.002 [16] 孟杰,金涛. 镍基单晶高温合金的再结晶[J]. 材料工程,2011(6): 92-98. doi: 10.3969/j.issn.1001-4381.2011.06.019MENG Jie,JIN Tao. Recrystallization of single crystal nickel-based superalloys[J]. Journal of Materials Engineering,2011(6): 92-98. (in Chinese) doi: 10.3969/j.issn.1001-4381.2011.06.019 [17] 马健,李世峰,何爱杰. DD6单晶涡轮叶片缘板裂纹与再结晶研究[J]. 航空动力学报,2012,27(5): 1069-1073. doi: 10.13224/j.cnki.jasp.2012.05.018MA Jian,LI Shifeng,HE Aijie. Platform crack and recrystallization of DD6 single crystal turbine blade[J]. Journal of Aerospace Power,2012,27(5): 1069-1073. (in Chinese) doi: 10.13224/j.cnki.jasp.2012.05.018 [18] FEDELICH B. A microstructure model for the monotonic and the cyclic mechanical behavior of single crystals of super alloys at high temperatures[J]. International Journal of Plasticity,2002,18: 1-4. doi: 10.1016/S0749-6419(00)00045-0