选区激光熔化GH4169合金微观组织及裂纹萌生扩展行为研究
陈晓倩,白朴存*,赵学平,郭文强,郭宇豪,柯尊东,郭文霞,曹 宇
(1. 内蒙古工业大学 材料科学与工程学院,内蒙古 呼和浩特 010051;2. 内蒙古工业大学 工程训练教学部,内蒙古 呼和浩特010051;3. 呼伦贝尔学院 机电工程学院,内蒙古 呼伦贝尔021008)
摘 要 本文采用选区激光熔化技术制备GH4169合金,并对沉积态合金进行固溶+时效热处理。利用扫描电镜(SEM)和透射电镜(TEM)分析时效态GH4169合金的微观组织,使用配备原位拉伸台的扫描电镜(In-situ SEM)研究时效态合金微观组织对裂纹萌生扩展行为的影响。结果表明:时效态GH4169合金的晶界上存在大量短棒状δ相,晶内存在一些长针状的δ相;晶内除δ相之外,还存在大量弥散分布的纳米级强化相(γ″相和γ′相)。GH4169合金裂纹萌生的主要因素为孔隙和晶界上的δ相,孔隙破坏了合金微观组织的连续性,容易引起应力集中;晶界处的δ相尺寸较大、界面能较高,在外力作用下位错不断增殖,使得晶界处成为应力集中区。裂纹的扩展方式存在沿晶和穿晶两种;时效态GH4169合金拉伸断口主要由解理面、撕裂棱和韧窝组成,其断裂方式为混合型断裂。
关键词 选区激光熔化;GH4169合金;微观组织;裂纹萌生扩展;断口
中图分类号:TG132.32;TG115.21+5.3 文献标识码:Adoi:10.3969/j.issn.1000-6281.2022.03.004
Microstructure and crack evolution behavior of GH4169 superalloy prepared by selective laser melting
CHEN Xiao-qian1,BAI Pu-cui1*,ZHAO Xue-ping1,GUO Wen-qiang1,GUO Yu-hao1,KE Zun-dong1,GUO Wen-xia2,CAO Yu3
(1. College of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot Neimongol 010051;2. Engineering Training and Teaching Department, Inner Mongolia University of Technology, Hohhot Neimongol 010051;3. Institute of Mechanical and Electrical Engineering, Hulunbeier College, Hulunbeier Neimongol 021008, China)
Abstract GH4169 alloy was prepared by selective laser melting technology, and the deposited alloy was subjected to solid solution and aging heat treatment in sequence. The microstructure of the aged GH4169 alloy was analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the effect of microstructure on crack initiation and propagation behavior of the aged GH4169 alloy were studied by in-situ SEM. The results show that there are a large number of short rod-like δ phases at the grain boundary and some long needle-like δ phases in the grain. In addition to δ phase, there are also a large number of nanoscale strengthening phases (γ′′ phase and γ′ phase) dispersed in γ matrix. The main factors for the crack initiation of the aged GH4169 alloy are pores and grain boundary. The pores destroy the continuity of the microstructure and are easy to cause stress concentration. The size of δ phase at grain boundary is large and the interface energy is high. Under the action of an external force, the dislocation proliferation causes the grain boundary to become a stress concentration area. Intergranular propagation and transgranular propagation are the two modes of crack propagation. The tensile fracture of the aged GH4169 alloy mainly includes tearing edges and dimples, and the fracture mode is mixed fracture.
Keywords selective laser melting;GH4169 alloy;microstructure;crack initiation and propagation;fracture
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[1] 樊恩想, 刘小欣, 吴欢欢. 激光选区熔化增材制造技术的发展[J]. 机械制造, 2021, 59(8): 45-49.
[2] 胡腾腾. 激光立体成形Ti-15Mo合金显微组织及力学性能研究[D]. 西安: 长安大学, 2020.
[3] WANG Y C, LEI L M, SHI L, et al. Scanning strategy dependent tensile properties of selective laser melted GH4169[J]. Materials Science and Engineering A, 2020, 788: 139616.
[4] TANJA T, JOHANNES S, RANINER V, et al. Microstructure and mechanical properties of selective laser melted inconel 718 compared to forging and casting[J]. Materials Letters, 2016, 164: 428-431.
[5] 丁青青, 贝红斌, 赵新宝, 等. 透射电子显微学在镍基单晶高温合金领域的应用进展和展望[J]. 电子显微学报, 2020, 39(5): 586-602.
[6] SHEN X F, CHENG Z Y, WANG C G. Effect of heat treatments on the microstructure and mechanical properties of Al-Mg-Sc-Zr alloy fabricated by selective laser melting[J]. Optics and Laser Technology, 2021, 143: 518-523.
[7] 高天明, 程晓农, 罗锐, 等. 时效处理对GH4169合金显微组织及高温拉伸变形行为的影响[J]. 金属热处理, 2020, 45(8): 119-123.
[8] 王建国, 刘东, 王海平, 等. GH4169合金晶界δ相析出的动力学分析[J]. 稀有金属材料与工程, 2019, 48(4): 1148-1154.
[9] 张凤英, 陈静, 谭华, 等. 钛合金激光快速成形过程中缺陷形成机理研究[J]. 稀有金属材料与工程, 2007(2): 211-215.
[10] 周鹏杰, 于金江, 孙晓峰, 等. M951镍基高温合金的高温高周疲劳性能[J]. 机械工程材料, 2013, 37(7): 77-81.
[11] ZHU L, WU Z R, HU X T, et al. Investigation of small fatigue crack initiation and growth behavior of nickel base superalloy GH4169[J]. Fatigue & Fracture of Engineering Materials and Structures, 2016, 39(9): 1150-1160.
[12] 侯杰, 董建新, 姚志浩. GH4169合金高温疲劳裂纹扩展的微观损伤机制[J]. 工程科学学报, 2018, 40(7): 822-832.
[13] 赵新宝, 岳亮, 夏万顺, 等. 固溶处理对一种第四代镍基单晶高温合金微观组织和偏析的影响[J]. 电子显微学报, 2020, 39(5): 462-469.
[14] GUO J D, SHAN T T, XIAN C Z. et al. Grain size effect on the small fatigue crack initiation and growth mechanisms of nickel-based superalloy GH4169[J]. Engineering Fracture Mechanics, 2015, 134: 433-450.
[15] 李阳, 魏志坚, 徐平伟, 等. 热变形对GH4169合金中NbC析出相尺寸形貌影响[J]. 稀有金属材料与工程, 2020, 49(5): 1773-1780.
[16] 李亚敏, 朱瑞明, 刘洪军, 等. 长期时效过程中GH625合金的析出相演变[J]. 金属热处理, 2017, 42(9): 94-99.
[17] AMIRJAN M, BOZORG M, SAKIANI H. Investigation of microstructure and corrosion behavior of IN718 superalloy fabricated by selective laser melting[J]. Materials Chemistry and Physics, 2021, 263: 124368.
[18] SHEN Y, JIAN G G, XIAN C Z. Effect of stress ratio on the fatigue crack propagation behavior of the nickel-based GH4169 alloy[J]. Acta Metallurgica Sinica, 2017, 30(9): 809-821.
[19] JIAN Z M, QIAN G A, PAOLINO D S, et al. Crack initiation behavior and fatigue performance up to very-high-cycle regime of AlSi10Mg fabricated by selective laser melting with two powder sizes[J]. International Journal of Fatigue, 2021, 143: 1060134.
[20] 吴楠. 微观组织和初始缺陷对镍基合金GH4169疲劳裂纹萌生及扩展行为的影响[D]. 上海: 华东理工大学, 2016.
[21] WANG X, HE X, WANG T, et al. Internal pores in DED Ti-6.5Al-2Zr-Mo-V alloy and their influence on crack initiation and fatigue life in the mid-life regime[J]. Additive Manufacturing, 2019, 28: 373-393.
[22] 马晋遥, 王晋, 赵云松, 等. 一种第二代镍基单晶高温合金1150℃原位拉伸断裂机制研究[J]. 金属学报, 2019, 55(8): 987-996.
[23] GUO J D, SHAN T T, XIAN C Z, et al. Small fatigue crack initiation and growth mechanisms of nickel-based superalloy GH4169 at 650°C in air[J]. Engineering Fracture Mechanics, 2016, 153:35-49.
[24] XU M, ZHU C Y, GONG Y F, et al. Influence of grain size on the small fatigue crack initiation and propagation behaviors of a nickel-based superalloy at 650℃[J]. Journal of Materials Science & Technology, 2019, 35(8): 1607-1617.
[25] Chen Q Z, Kong Y H, Jones C N, et al. Porosity reduction by minor additions in RR2086 superalloy[J]. Scripta Materialia, 2004, 51: 155.
[26] 陈建军, 丁雨田, 王琨, 等. 原位拉伸法研究GH3625合金退火孪晶界稳定性及断裂行为[J]. 稀有金属材料与工程, 2021, 50(4): 1311-1317.
[27] 鲁耀钟, 雷卫宁, 任维彬, 等. 激光熔覆Inconel 718合金裂纹分析及裂纹控制研究[J]. 表面技术, 2020, 49(9): 233-243.
[28] RAJPUT A, PAUL S K. Deformation inhomogeneity at the crack tip of polycrystalline copper[J]. Materials Today Communications, 2021, 26: 101781.
[29] CAUTHEN C, ANDERSON K V, AVERY D Z, et al. Fatigue crack nucleation and microstructurally small crack growth mechanisms in high strength aluminum alloys[J]. International Journal of Fatigue, 2020, 140: 05790.
[30] 李剑. IN718合金的选区激光熔化成形工艺及性能研究[D]. 哈尔滨:哈尔滨理工大学, 2018.
[31] 吴楠, 张显程, 涂善东, 等. 室温和650℃下晶粒尺寸对GH4169合金疲劳小裂纹萌生和扩展行为的影响[J]. 机械工程学报, 2016, 52(20): 66-75.
[32] 陈宇杰, 党理, 张泽, 等. 第三代镍基单晶高温合金原位加温-拉伸的研究[J]. 电子显微学报, 2020, 39(3): 233-237.