ISSN: 1003-6326
CN: 43-1239/TG

Vol. 30    No. 8    August 2020

Microstructure and shear strength of γ-TiAl/GH536 joints brazed with Ti-Zr-Cu-Ni-Fe-Co-Mo filler alloy
Li LI1,2, Wei ZHAO1, Zhi-xue FENG1, Jia SUN3, Xiao-qiang LI2
(1. School of Materials Science and Engineering, East China Jiaotong University, Nanchang 330013, China;
2. National Engineering Research Center of Near-net-shape Forming for Metallic Materials, South China University of Technology, Guangzhou 510640, China;
3. Bogie Design Department, CRRC Nanjing Puzhen Co. Ltd., Nanjing 210031, China
Abstract: The influence of brazing temperature and brazing time on the microstructure and shear strength of γ-TiAl/GH536 joints brazed with Ti-Zr-Cu-Ni-Fe-Co-Mo filler was investigated using SEM, EDS, XRD and universal testing machine. Results show that all the brazed joints mainly consist of four reaction layers regardless of the brazing temperature and brazing time. The thickness of the brazed seam and the average shear strength of the joint increase firstly and then decrease with brazing temperature in the range of 1090-1170 °C and brazing time varying from 0 to 20 min. The maximum shear strength of 262 MPa is obtained at 1150 °C for 10 min. The brittle Al3NiTi2 and TiNi3 intermetallics are the main controlling factors for the crack generation and deterioration of joint strength. The fracture surface is characterized as typical cleavage fracture and it mainly consists of massive brittle Al3NiTi2 intermetallics.
Key words: γ-TiAl alloy; Ni-based superalloy; vacuum brazing; amorphous filler; microstructure; shear strength
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
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