摘要
激光熔化沉积相比传统的氩弧焊、微束等离子弧焊更适用于单晶合金薄壁基体的修复。采用激光熔化沉积技术进行DD6单晶高温合金的增材修复。利用光学显微镜、扫描电镜与EBSD分析增材修复接头的修复区与热影响区组织特征,并测试修复接头的显微硬度分布与高温拉伸性能。结果表明:紧邻修复界面基体热影响区的γ′相发生了部分粗化与溶解,硬度明显降低。激光熔化沉积修复组织为外延生长的定向柱晶组织,由γ+γ′相以及枝晶间的少量弥散分布的碳化物组成,修复组织中存在低倍可见的细长柱状杂向晶,多数分布于紧邻界面的位置;随着修复区高度的增加,外延生长组织的枝晶间距与硬度随着修复高度的增加而逐渐增大,枝晶中细小的网格状γ′相占比不断增加;修复接头980℃抗拉强度达到了母材标准值的102%,屈服强度达到了母材标准值的92%,但伸长率相对较弱。
Laser melting deposition is more suitable for repairing thin-walled substrates of single crystal alloys compared to argon arc welding and micro plasma arc welding.This article used laser melting deposition technology for additive repair of DD6 single crystal superalloy.The microstructure characteristics of the repaired zone and heat affected zone of the additive repaired joint were analysed by optical microscopy,scanning electron microscopy,and EBSD.And the microhardness distribution and high-temperature tensile properties of the repaired joint were tested.The results indicate that in the heat affected zone adjacent to the repair interface,γ′phase is partially coarsened and dissolved,and the hardness decreases significantly.The microstructure of repaired zone is an oriented columnar crystal structure grown epitaxially,and composed ofγ+γ′phase and a small amount of dispersed carbides between dendrites.Many elongated columnar stray grains remain in the repaired zone,mostly distribute near the fusion line.As the height of the repaired zone increases,the dendrite spacing and hardness of the epitaxial growth tissue increases gradually,and the proportion of fine gridγ′phase in the dendrites increases continuously.The tensile strength of the repaired joint at 980℃reaches 102%of the base material,and the yield strength reaches 92%of the base material,but the elongation is relatively poor.
作者
曲致奇
秦仁耀
张学军
陈冰清
黄帅
张国会
QU Zhiqi;QIN Renyao;ZHANG Xuejun;CHEN Bingqing;HUANG Shuai;ZHANG Guohui(3D Printing Research&Engineering Technology Center,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2024年第12期29-36,共8页
Journal of Materials Engineering
基金
国家科技重大专项项目(J2019-Ⅶ-0010-0150)。
关键词
DD6单晶高温合金
激光熔化沉积
增材修复接头
组织和性能
DD6 single crystal superalloy
laser melting deposition
additive repaired joint
microstructure and mechanical property
