激光近净成形GH99合金的裂纹分析
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摘要
对GH99合金在激光近净成形过程中裂纹形成的原因进行了研究和讨论,提出了优化工艺参数的解决办法。结果表明:内部裂纹呈现为短线状-针状,其在柱状晶晶界或二次枝晶间形成,垂直于沉积方向,沿细密的定向组织晶界分布和扩展;在晶界上Al和Ti元素的富集容易析出γ′(Ni_3(AlTi))相,弱化了晶界,使晶界熔化并在凝固时难以补缩,造成裂纹形核;在快速的热循环过程中,残余应力的不断累积造成裂纹沿晶界扩展;通过优化工艺参数以降低热输入,可以克服GH99合金在激光近净成形中的热裂纹形成,实现构件的无裂纹增材成形。
The causes of crack formation in GH99 alloy during laser engineered net shaping were studied and discussed, and the solution to optimize process parameters was proposed. The results show that the internal cracks are short linear-needle-like, forming in columnar grain boundaries or secondary dendrites, perpendicular to the direction of deposition, and distributed and propagated along the fine oriented grain boundaries. The enrichment of Al and Ti elements at grain boundaries tends to precipitate γ′(Ni_3(AlTi) phase,which weakens grain boundary, melts the grain boundary and is difficult to be shrank during solidification, resulting in crack nucleation. In the process of rapid thermal cycling, the accumulation of residual stress causes the crack to propagate along the grain boundary. By optimizing the process parameters to reduce the heat input, the thermal crack formation of the GH99 alloy during laser engineered net shaping can be overcome, and the crack-free forming of the components can be realized.
The causes of crack formation in GH99 alloy during laser engineered net shaping were studied and discussed, and the solution to optimize process parameters was proposed. The results show that the internal cracks are short linear-needle-like, forming in columnar grain boundaries or secondary dendrites, perpendicular to the direction of deposition, and distributed and propagated along the fine oriented grain boundaries. The enrichment of Al and Ti elements at grain boundaries tends to precipitate γ′(Ni_3(AlTi) phase,which weakens grain boundary, melts the grain boundary and is difficult to be shrank during solidification, resulting in crack nucleation. In the process of rapid thermal cycling, the accumulation of residual stress causes the crack to propagate along the grain boundary. By optimizing the process parameters to reduce the heat input, the thermal crack formation of the GH99 alloy during laser engineered net shaping can be overcome, and the crack-free forming of the components can be realized.
引文
[1] 崔令江,林熙原,朱强,等.高温合金热处理工艺研究进展[J].材料导报,2016,30(7):106-110.CUI Ling-jiang,LIN Xi-yuan,ZHU Qiang,et al.Research progress on heat treatment process of superalloys[J].Materials Review,2016,30(7):106-110.
[2] 陈国良,林均品.有序金属间化合物结构材料物理金属学基础[M].北京:冶金工业出版社,1999.
[3] 《中国航空材料手册》编委委员会.中国航空材料手册:变形高温合金、铸造高温合金[M].北京:中国标准出版社,2011:278-293.
[4] 马明明.两种典型金属零部件激光增材制造技术基础比较研究[D].武汉:华中科技大学,2016.MA Ming-ming.A comparative study on fundamentals of two typical laser additive manufacturing technologies of metallic conponents[D].Wuhan:Huazhong University of Science and Technology,2016.
[5] 赵晓明,陈静,何飞,等.激光快速成形Rene88DT高温合金开裂机理研究[J].稀有金属材料与工程,2007,36(2):216-220.ZHAO Xiao-ming,CHEN Jing,HE Fei,et al.The cracking mechanism of Rene 88DT superalloy by laser rapid forming[J].Rare Metal Materials and Engineering,2007,36(2):216-220.
[6] 黄卫东,林鑫.激光立体成形高性能金属零件研究进展[J].中国材料进展,2010,29 (6):12-27.HUANG Wei-dong,LIN Xin.Research progress in laser solid forming of high performance metallic component[J].Materials China,2010,29 (6):12-27.
[7] 施凡赵吉宾王志国.K465合金激光增材制造加工工艺研究[J].机械科学与技术,2017,36(8):1298-1302.SHI Fan,ZHAO Ji-bin,WANG Zhi-guo.Research on processing technology of superalloy K465 via laser additive manufacturing[J].Mechanical Science and Technology for Aerospace Engineering,2017,36(8):1298-1302.
[8] 明宪良,陈静,谭华.激光立体成形GH4169高温合金γ″相的高温粗化行为[J].材料工程,2014,8(8):8-14.MING Xian-liang,CHEN Jing,TAN Hua.Coarsening behavior of γ″precipitates in GH4169 superalloy pabricated by laser solid forming[J].Journal of Materials Engineering,2014,8(8):8-14.
[9] 于承雪,景财年,李怀学,等.激光熔覆裂纹的形成机理及控制方法[J].航空制造技术,2012,17(4):75-79.YU Cheng-xue,JING Cai-nian,LI Huai-xue,et al.Formation mechanism and control method of laser cladding crack[J].Aeronautical Manufacturing Technology,2012,17 (4):75-79.
[10] 郭晓凡.熔体过热处理对镍基高温合金组织与力学性能的影响[D].兰州:兰州理工大学,2016.GUO Xiao-fan.Effect of melt superheat treatment on microstructure and mechanical properties of nickel-based superalloy[D].Lanzhou:Lanzhou University of Technology,2016.
[11] 杨福,刘恩克,徐骏,等.Sc、Zr和Er微合金化Al-5Mg填充合金的焊接热裂敏感性[J].中国有色金属学报,2010,20(4):620-627.YANG Fu,LIU En-ke,XU Jun,et al.Hot-cracking susceptibility of (Sc,Zr,Er)-micro alloyed Al-5Mg filler metals[J].The Chinese Journal of Nonferrous Metals,2010,20(4):620-627.
[12] 张弘斌.GH99高温合金高温变形行为及组织演化规律研究[D].哈尔滨:哈尔滨工业大学,2015.ZHANG Hong-bin.Study on high temperature deformation behavior and microstructure evolution of GH99 superalloy[D].Harbin:Harbin Institute of Technology,2015.
[13] 孙鸿卿,钟敏霖,刘文今,等.定向凝固镍基高温合金上激光熔覆Inconel 738的裂纹敏感性研究[J].航空材料学报,2005,25(2):28-33.SUN Hong-qing,ZHONG Min-lin,LIU Wen-jin,et al.Study on the crack sensitivity of laser cladding Inconel 738 on directionally solidified Ni base superalloy[J].Journal of Aeronautical Materials,2005,25(2):28-33.
[14] 林鑫,黄卫东.高性能金属构件的激光增材制造[J].中国科学:信息科学,2015,45(9):1111-1126.LIN Xin,HUANG Wei-dong.Laser additive manufacturing of high performance metal components[J].Chinese Science of Information Science,2015,45(9):1111-1126.
[15] 闫春泽.粉末激光烧结增材制造技术[M].武汉:华中科技大学出版社,2013.
[2] 陈国良,林均品.有序金属间化合物结构材料物理金属学基础[M].北京:冶金工业出版社,1999.
[3] 《中国航空材料手册》编委委员会.中国航空材料手册:变形高温合金、铸造高温合金[M].北京:中国标准出版社,2011:278-293.
[4] 马明明.两种典型金属零部件激光增材制造技术基础比较研究[D].武汉:华中科技大学,2016.MA Ming-ming.A comparative study on fundamentals of two typical laser additive manufacturing technologies of metallic conponents[D].Wuhan:Huazhong University of Science and Technology,2016.
[5] 赵晓明,陈静,何飞,等.激光快速成形Rene88DT高温合金开裂机理研究[J].稀有金属材料与工程,2007,36(2):216-220.ZHAO Xiao-ming,CHEN Jing,HE Fei,et al.The cracking mechanism of Rene 88DT superalloy by laser rapid forming[J].Rare Metal Materials and Engineering,2007,36(2):216-220.
[6] 黄卫东,林鑫.激光立体成形高性能金属零件研究进展[J].中国材料进展,2010,29 (6):12-27.HUANG Wei-dong,LIN Xin.Research progress in laser solid forming of high performance metallic component[J].Materials China,2010,29 (6):12-27.
[7] 施凡赵吉宾王志国.K465合金激光增材制造加工工艺研究[J].机械科学与技术,2017,36(8):1298-1302.SHI Fan,ZHAO Ji-bin,WANG Zhi-guo.Research on processing technology of superalloy K465 via laser additive manufacturing[J].Mechanical Science and Technology for Aerospace Engineering,2017,36(8):1298-1302.
[8] 明宪良,陈静,谭华.激光立体成形GH4169高温合金γ″相的高温粗化行为[J].材料工程,2014,8(8):8-14.MING Xian-liang,CHEN Jing,TAN Hua.Coarsening behavior of γ″precipitates in GH4169 superalloy pabricated by laser solid forming[J].Journal of Materials Engineering,2014,8(8):8-14.
[9] 于承雪,景财年,李怀学,等.激光熔覆裂纹的形成机理及控制方法[J].航空制造技术,2012,17(4):75-79.YU Cheng-xue,JING Cai-nian,LI Huai-xue,et al.Formation mechanism and control method of laser cladding crack[J].Aeronautical Manufacturing Technology,2012,17 (4):75-79.
[10] 郭晓凡.熔体过热处理对镍基高温合金组织与力学性能的影响[D].兰州:兰州理工大学,2016.GUO Xiao-fan.Effect of melt superheat treatment on microstructure and mechanical properties of nickel-based superalloy[D].Lanzhou:Lanzhou University of Technology,2016.
[11] 杨福,刘恩克,徐骏,等.Sc、Zr和Er微合金化Al-5Mg填充合金的焊接热裂敏感性[J].中国有色金属学报,2010,20(4):620-627.YANG Fu,LIU En-ke,XU Jun,et al.Hot-cracking susceptibility of (Sc,Zr,Er)-micro alloyed Al-5Mg filler metals[J].The Chinese Journal of Nonferrous Metals,2010,20(4):620-627.
[12] 张弘斌.GH99高温合金高温变形行为及组织演化规律研究[D].哈尔滨:哈尔滨工业大学,2015.ZHANG Hong-bin.Study on high temperature deformation behavior and microstructure evolution of GH99 superalloy[D].Harbin:Harbin Institute of Technology,2015.
[13] 孙鸿卿,钟敏霖,刘文今,等.定向凝固镍基高温合金上激光熔覆Inconel 738的裂纹敏感性研究[J].航空材料学报,2005,25(2):28-33.SUN Hong-qing,ZHONG Min-lin,LIU Wen-jin,et al.Study on the crack sensitivity of laser cladding Inconel 738 on directionally solidified Ni base superalloy[J].Journal of Aeronautical Materials,2005,25(2):28-33.
[14] 林鑫,黄卫东.高性能金属构件的激光增材制造[J].中国科学:信息科学,2015,45(9):1111-1126.LIN Xin,HUANG Wei-dong.Laser additive manufacturing of high performance metal components[J].Chinese Science of Information Science,2015,45(9):1111-1126.
[15] 闫春泽.粉末激光烧结增材制造技术[M].武汉:华中科技大学出版社,2013.