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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2022, Vol. 43 ›› Issue (4): 525806.doi: 10.7527/S1000-6893.2021.25806

• Articles • Previous Articles     Next Articles

Interfacial microstructure and mechanical properties of vacuum-brazed Al2O3 ceramic and GH3536 joint

YANG Siyuan, WANG Ying, WANG Jilai, YANG Zhenwen, WANG Dongpo   

  1. Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300354, China
  • Received:2021-05-13 Revised:2021-05-20 Published:2021-05-31
  • Supported by:
    National Natural Science Foundation of China (51875400); Science and Technology Program of Tianjin (19ZXJRGX00100)

Abstract: A silver-based active brazing filler alloy Ag-5.0Cu-1.0Al-1.25Ti was used to join Al2O3 ceramic and nickel-based superalloy (GH3536) by vacuum brazing. To clarify the formation mechanism of the interface of the brazed joint, the interfacial microstructure and phases composition of the joint were studied by scanning electron microscopy and X-ray diffraction analysis. Meanwhile, the effect of brazing temperature and holding time on the microstructure and mechanical properties of the joint was also analyzed, so as to optimize the brazing parameters. The results showed that the typical microstructure of the Al2O3/GH3536 joint obtained at 970℃ for 10 min was Al2O3/Ti3(Cu,Al)3O/Ag(s,s)+AlCu2Ti/TiNi3+TiFe2/GH3536, and the maximum shear strength of the joint could reach 194 ±10 MPa. With the increase of brazing temperature and holding time, the thickness of Ti3(Cu,Al)3O reaction layer increased, the Cu-rich phase gradually decreased, and AlCu2Ti compounds aggregated. However, the brazing temperature was too high or the holding time was too long, the silver matrix in the brazing seam was replaced by a large amount of AlCu2Ti compound, which resulted in a significant decrease in the mechanical properties of the joint. Finally, the failure mechanism of the joint was analyzed. Under the action of shear force, the fracture of the joint occurred mainly at the interface of Al2O3 ceramic and Ti3(Cu,Al)3O reaction layer and the Al2O3 ceramic substrate.

Key words: vacuum active brazing, nickel-based superalloy, AgCuAlTi brazing, alumina ceramic, shear strength

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