Please wait a minute...
金属学报  2020, Vol. 56 Issue (3): 301-310    DOI: 10.11900/0412.1961.2019.00287
  研究论文 本期目录 | 过刊浏览 |
高温合金单晶铸件中条纹晶的形成机制
马德新1,2,王富3,徐维台1,徐文梁3,赵运兴1()
1. 深圳万泽中南研究院 深圳 518045
2. 中南大学粉末冶金研究院 长沙 410083
3. 西安交通大学机电工程学院 西安 710049
Formation of Sliver Defects in Single CrystalCastings of Superalloys
MA Dexin1,2,WANG Fu3,XU Weitai1,XU Wenliang3,ZHAO Yunxing1()
1. Wedge Central South Research Institute, Shenzhen 518045, China
2. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China
3. School of Mechanic and Electronic Engineering, Xi’an Jiao Tong University, Xi’an 710049, China
引用本文:

马德新,王富,徐维台,徐文梁,赵运兴. 高温合金单晶铸件中条纹晶的形成机制[J]. 金属学报, 2020, 56(3): 301-310.
Dexin MA, Fu WANG, Weitai XU, Wenliang XU, Yunxing ZHAO. Formation of Sliver Defects in Single CrystalCastings of Superalloys[J]. Acta Metall Sin, 2020, 56(3): 301-310.

全文: PDF(32837 KB)   HTML
摘要: 

对高温合金单晶叶片铸件中条纹晶起源处的微观组织进行了观察分析,提出了这种晶粒缺陷的产生机理。通过微观检测确认了条纹晶的出现是由于铸件表面单个枝晶主干在糊状区内被撕断,但又被残余液体焊合,呈现出明显的起点。导致这种撕裂的主要原因是型壳粘连引起的枝晶收缩严重受阻或是由夹杂切割引起的枝晶强度严重受损,从而形成了条纹晶缺陷产生的2种主要机制。撕裂后的枝晶会发生一定程度的整体偏转,在基体组织上形成一个由小角度晶界封闭而成的狭长晶粒。比较了条纹晶与其它晶粒缺陷的相似和不同之处,并讨论了减少条纹晶缺陷应该采取的工艺措施。

关键词 条纹晶高温合金单晶叶片晶体缺陷    
Abstract

In the casting components of superalloys with increasing content of the refractory elements the occurrence of sliver defects becomes rather frequent. In comparison to the other grain defects such as stray grains and freckles, the sliver defect was less well understood and its formation mechanism is still unclear. In the present work, the origins of the sliver defects in the single crystal (SC) castings were investigated. In the metallographic detection, sliver grains can be identified to be miss-alignments of isolated, individual primary dendrite on the SC matrix. The sliver defects originated from the tearing of the existing dendrite stems in the mush zone, revealing a clear starting point of sliver defect. The cracks of the dendrites were filled by the interdendritic residual melt, which finally solidified into γ′-stripes. The tearing of some existing dendrite stems can be attributed to the adhesion of shell mold that hinders the shrinkage of the columnar dendrites on the casting surface. The second reason for the dendrite tearing is the insertion of oxide residues which significantly weakens the strength of the dendrite stems. Due to the support of the neighboring columnar dendrites, the tilting of the broken dendrites is limited, so that the grain boundary between a sliver and the matrix structure has normally a low angle. The structure and formation mechanisms of sliver defects were discussed in comparison with other defects such as stray grains, freckles and low angle grain boundaries. The corresponding methods were proposed to avoid sliver defects in production of SC superalloy castings.

Key wordssliver    superalloy    single crystal    grain defect
收稿日期: 2019-09-02     
ZTFLH:  TG146  
基金资助:国家自然科学基金项目(91860103);深圳科技创新委员会项目(20150128085205453)
作者简介: 马德新,男,1955年生,教授,博士
AlloyCrCoWMoAlTiTaHfReNi
DD57.027.525.031.526.23-6.510.153.01Bal.
CMSX-46.499.716.410.635.601.016.520.102.97Bal.
表1  所用合金的的化学成分 (mass fraction / %)
图1  叶片上起源于Pt丝芯撑和凸包部位的条纹晶
图2  叶片上的条纹晶缺陷及其OM放大图和SEM像
图3  另一例条纹晶缺陷及起源处的放大OM像
图4  叶片上起源于氧化夹杂的条纹晶
图5  条纹晶缺陷及其起源处的OM像和SEM像
图6  图5e中试样截面的EDS扫描结果
图7  模壳粘连引起条纹晶的示意图
图8  夹杂嵌入枝晶引起条纹晶的示意图
图9  枝晶横向收缩(包括法向和切向收缩)引起的条纹晶产生机制示意图
[1] Carney C A, Beech J. The origin of sliver defects in single crystal turbine blades [A]. Solidification Processing [C]. London: Institute of Metals, 1987: 33
[2] Shi Z X, Liu S Z, Li J R. Sliver formation mechanism of single crystal superalloy during directional solidification proscess [J]. Hot Work. Technol., 2013, 42(13): 31
[2] 史振学, 刘世忠, 李嘉荣. 单晶高温合金定向凝固过程中条带的形成机制 [J]. 热加工工艺, 2013, 42(13): 31
[3] Avedon J W, Tenant P A, Foss B J, et al. On the origin of sliver defects in single crystal investment castings [J]. Acta Mater., 2013, 61: 5162
[4] Zhang J, Lou L H. Basic research in development and application of cast superalloy [J]. Acta Metall. Sin., 2018, 54: 1637
[4] 张 健, 楼琅洪. 铸造高温合金研发中的应用基础研究 [J]. 金属学报, 2018, 54: 1637
[5] Ma D X, Wang F, Sun H Y, et al. Study on sliver defects in single crystal castings of superalloys [J]. Foundry, 2019, 68: 567
[5] 马德新, 王 富, 孙洪元等. 高温合金单晶铸件中条纹晶缺陷的试验研究 [J]. 铸造, 2019, 68: 567
[6] Paul U, Sahm P R, Goldschmidt D. Inhomogeneities in single-crystal components [J]. Mater. Sci. Eng., 1993, A173: 49
[7] Meyer M, Dedecke D, Paul U, et al. Undercooling related casting defects in single crystal turbine blades [A]. Superalloys 1996 [C]. New York: TMS, 1996: 471
[8] Ma D X, Bührig-Polaczek A. Application of a heat conductor technique in the production of single-crystal turbine blades [J]. Metall. Mater. Trans., 2009, 40B: 738
[9] Zhang X L, Zhou Y Z, Jin T, et al. Study on the tendency of stray grain formation of Ni-based single crystal superalloys [J]. Acta Metall. Sin., 2012, 48: 1229
[9] 张小丽, 周亦胄, 金 涛等. 镍基单晶高温合金杂晶形成倾向性的研究 [J]. 金属学报, 2012, 48: 1229
[10] Zhang H Q, Zhang J, Li Y F, et al. Stray grain formation in casting platform of third generation Ni-base single crystal superalloy [J]. Foundry, 2014, 63: 128
[10] 张宏琦, 张 军, 李亚峰等. 一种第三代镍基单晶高温合金铸件截面突变处的杂晶形成过程 [J]. 铸造, 2014, 63: 128
[11] Ma D X. Development of single crystal solidification technology for production of superalloy turbine blades [J]. Acta Metall. Sin., 2015, 51: 1179
[11] 马德新. 高温合金叶片单晶凝固技术的新发展 [J]. 金属学报, 2015, 51: 1179
[12] Ma D X, Zhang Q Y, Wang H Y, et al. Influence of process condition on the stray grain formation in the single crystal blades of Ni-base superalloy DD483 [J]. Foundry, 2017, 66: 439
[12] 马德新, 张琼元, 王海洋等. 工艺条件对镍基高温合金DD483单晶叶片中杂晶缺陷的影响 [J]. 铸造, 2017, 66: 439
[13] Ma D X, Wang F, Sun H Y, et al. Experimental investigations on stray grain defects in single crystal castings of superalloys [J]. Foundry, 2019, 68: 558
[13] 马德新, 王 富, 孙洪元等. 高温合金单晶铸件中杂晶缺陷的试验研究 [J]. 铸造, 2019, 68: 558
[14] Giamei A F, Kear B H. On the nature of freckles in nickel base superalloys [J]. Metall. Trans., 1970, 1: 2185
[15] Copley S M, Giamei A F, Johnson S M, et al. The origin of freckles in unidirectionally solidified castings [J]. Metall. Trans., 1970, 1: 2193
[16] Auburtin P B L. Determination of the influence of growth front angle on freckle formation in superalloys [D]. Vancouver, Canada: The University of British Columbia, 1998
[17] Auburtin P, Wang T, Cockcroft S L, et al. Freckle formation and freckle criterion in superalloy castings [J]. Metall. Mater. Trans., 2000, 31B: 801
[18] Beckermann C, Gu J P, Boettinger W J. Development of a freckle predictor via rayleigh number method for single-crystal nickel-base superalloy castings [J]. Metall. Mater. Trans., 2000, 31A: 2545
[19] Yang W H, Chang K M, Chen W, et al. Freckle criteria for the upward directional solidification of alloys [J]. Metall. Mater. Trans., 2001, 32A: 397
[20] Tin S, Pollock T M. Predicting freckle formation in single crystal Ni-base superalloys [J]. J. Mater. Sci., 2004, 39: 7199
[21] Reed R C. The Superalloys: Fundamentals and Applications [M]. London: Cambridge University Press, 2006: 140
[22] Ma D X, Wu Q, Bührig-Polaczek A. Some new observations on freckle formation in directionally solidified superalloy components [J]. Metall. Mater. Trans., 2012, 43B: 344
[23] Ma D X. Freckle formation during directional solidification of complex castings of superalloys [J]. Acta Metall. Sin., 2016, 52: 426
[23] 马德新. 定向凝固的复杂形状高温合金铸件中的雀斑形成 [J]. 金属学报, 2016, 52: 426
[24] Ma D X. Development of dendrite array growth during alternately changing solidification condition [J]. J. Crystal Growth, 2004, 260: 580
[25] Newell M, Devendra K, Jennings P A, et al. Role of dendrite branching and growth kinetics in the formation of low angle boundaries in Ni-base superalloys [J]. Mater. Sci. Eng., 2005, A412: 307
[26] D'Souza N, Newell M, Devendra K, et al. Formation of low angle boundaries in Ni-based superalloys [J]. Mater. Sci. Eng., 2005, A413-414: 567
[1] 白佳铭, 刘建涛, 贾建, 张义文. WTa型粉末高温合金的蠕变性能及溶质原子偏聚[J]. 金属学报, 2023, 59(9): 1230-1242.
[2] 马德新, 赵运兴, 徐维台, 王富. 重力对高温合金定向凝固组织的影响[J]. 金属学报, 2023, 59(9): 1279-1290.
[3] 陈佳, 郭敏, 杨敏, 刘林, 张军. 新型钴基高温合金中W元素对蠕变组织和性能的影响[J]. 金属学报, 2023, 59(9): 1209-1220.
[4] 卢楠楠, 郭以沫, 杨树林, 梁静静, 周亦胄, 孙晓峰, 李金国. 激光增材修复单晶高温合金的热裂纹形成机制[J]. 金属学报, 2023, 59(9): 1243-1252.
[5] 毕中南, 秦海龙, 刘沛, 史松宜, 谢锦丽, 张继. 高温合金锻件残余应力量化表征及控制技术研究进展[J]. 金属学报, 2023, 59(9): 1144-1158.
[6] 郑亮, 张强, 李周, 张国庆. /降氧过程对高温合金粉末表面特性和合金性能的影响:粉末存储到脱气处理[J]. 金属学报, 2023, 59(9): 1265-1278.
[7] 李嘉荣, 董建民, 韩梅, 刘世忠. 吹砂对DD6单晶高温合金表面完整性和高周疲劳强度的影响[J]. 金属学报, 2023, 59(9): 1201-1208.
[8] 宫声凯, 刘原, 耿粒伦, 茹毅, 赵文月, 裴延玲, 李树索. 涂层/高温合金界面行为及调控研究进展[J]. 金属学报, 2023, 59(9): 1097-1108.
[9] 冯强, 路松, 李文道, 张晓瑞, 李龙飞, 邹敏, 庄晓黎. γ' 相强化钴基高温合金成分设计与蠕变机理研究进展[J]. 金属学报, 2023, 59(9): 1125-1143.
[10] 赵鹏, 谢光, 段慧超, 张健, 杜奎. 两种高代次镍基单晶高温合金热机械疲劳中的再结晶行为[J]. 金属学报, 2023, 59(9): 1221-1229.
[11] 王磊, 刘梦雅, 刘杨, 宋秀, 孟凡强. 镍基高温合金表面冲击强化机制及应用研究进展[J]. 金属学报, 2023, 59(9): 1173-1189.
[12] 江河, 佴启亮, 徐超, 赵晓, 姚志浩, 董建新. 镍基高温合金疲劳裂纹急速扩展敏感温度及成因[J]. 金属学报, 2023, 59(9): 1190-1200.
[13] 张健, 王莉, 谢光, 王栋, 申健, 卢玉章, 黄亚奇, 李亚微. 镍基单晶高温合金的研发进展[J]. 金属学报, 2023, 59(9): 1109-1124.
[14] 穆亚航, 张雪, 陈梓名, 孙晓峰, 梁静静, 李金国, 周亦胄. 基于热力学计算与机器学习的增材制造镍基高温合金裂纹敏感性预测模型[J]. 金属学报, 2023, 59(8): 1075-1086.
[15] 刘兴军, 魏振帮, 卢勇, 韩佳甲, 施荣沛, 王翠萍. 新型钴基与Nb-Si基高温合金扩散动力学研究进展[J]. 金属学报, 2023, 59(8): 969-985.