Page 118 - 机械工程材料2024年第十一期

邱玉洁，等： Al-Si-Cu-Ni钎料成分和钎焊温度对高硅铝合金/可伐合金钎焊接头性能的影响

Effect of Al-Si-Cu-Ni Brazing Alloy Composition and Brazing Temperature on
Properties of High Silica Aluminum Alloy/Kovar Alloy Brazed Joints

QIU Yujie , NIU Jitai , YANG Huanyu , MU Erzhen 1
1, 2
1
3
(1. School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China;
2. Henan Jingtai Aerospace High-Tech Materials Technology Co., Ltd, Jiaozuo 454000, China;
3. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China)

Abstract: Al-7.5Si-23Cu-xNi (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5, mass fraction/%) foil brazing alloys were
prepared by melt spinning technology. The effect of Ni content on the microstructure and properties the brazing alloy was
analyzed. Vacuum brazing was conducted on CE11 high silicon aluminum alloy and 4J29 Kovar alloy by using the brazing
alloy with the best properties, and the effect of brazing temperature (560‒600 ℃) on the microstructure, shear strength
and air tightness of the joint was discussed. The results show that with the increase of Ni content, the change of liquid/
solid phase lines of the brazing alloy was small, the fusion temperature zone was stable, the local eutectic structure of the
as-cast brazing alloy increased, and the columnar crystals became coarse. With the increase of Ni content, the fracture
strain of the as-cast brazing alloy and the shear strength of the joint first increased and then decreased. When the Ni
mass fraction was 2.0%, the brazing alloy had the smallest fusion temperature zone, the lowest melting point, uniform
microstructures, more diffusely distributed eutectic phases, and the best toughness and welding performance. When
the brazing temperature was lower than 570 ℃, the Al-7.5Si-23Cu-2.0Ni brazing alloy could not melt completely and
the combination with base metal was poor. When the brazing temperature was higher than 570 ℃, the element diffusion
between the brazing alloy and the base metal was intense, resulting in silicon phase aggregation, and cracks appeared
in the weld. With the increase of brazing temperature, the shear strength of the joint first increased and then decreased,
and the leakage after welding first decreased and then increased. The best brazing temperature was 570 ℃, at this time
the weld was tightly combined with the base metals on both sides, the elements diffused uniformly, and the joint had the
largest shear strength and the best air tightness.
Key words: high-silicon aluminum alloy; Kovar alloy; Al-Si-Cu-Ni brazing alloy; brazing temperature; shear
strength

110