选区激光熔化GH4169合金微观组织及裂纹萌生扩展行为研究  

Microstructure and crack evolution behavior of GH4169 superalloy prepared by selective laser melting

作　　者：陈晓倩 白朴存[1] 赵学平 郭文强 郭宇豪 柯尊东 郭文霞 曹宇 CHEN Xiao-qian;BAI Pu-cui;ZHAO Xue-ping;GUO Wen-qiang;GUO Yu-hao;KE Zun-dong;GUO Wen-xia;CAO Yu(College of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot Inner Mongolia 010051;Engineering Training and Teaching Department,Inner Mongolia University of Technology,Hohhot Inner Mongolia 010051;Institute of Mechanical and Electrical Engineering,Hulunbuir College,Hulunbuir Inner Mongolia 021008,China)

机构地区：[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

出　　处：《电子显微学报》2022年第3期241-248,共8页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金资助项目(Nos.11672140,11762014);内蒙古自治区科技重大专项(No.ZDZX2018031);内蒙古自治区高等学校科学研究项目(No.NJZZ21019)。

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。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 cleavage face, tearing edges and dimples, and the fracture mode is mixed fracture.

关 键 词：选区激光熔化 GH4169合金 微观组织 裂纹萌生扩展 断口 

分 类 号：TG132.32[一般工业技术—材料科学与工程] TG115.215.3[金属学及工艺—合金]