(1. 青岛理工大学 机械与汽车工程学院，青岛 266520；
2. 哈尔滨工业大学 先进焊接及连接国家重点实验室，哈尔滨 150001)
摘 要: 采用Ni/Al/Zn复合钎料层对AZ31和2024合金实现了大气环境下、无钎剂的超声辅助瞬间液相扩散连接(U-TLP)，研究采用Ni层、Ni/Zn层、Zn/Ni/Zn层及Al/Zn/Ni/Zn层时钎缝的微观组织及接头的力学性能，分析Ni箔、Al箔及Zn箔在U-TLP过程中的作用。结果表明：通过调整Ni/Al/Zn复合钎料层的组合形式，可以实现对钎缝微观组织的调控及力学性能的改善，采用Al/Zn/Ni/Zn复合钎料层时钎缝剪切强度达到最高值(95.3 MPa)。Ni箔起到了“物理屏障”的作用，阻碍了Mg-Al金属间化合物(IMCs)的形成，但是由于铝合金一侧钎缝仅由Al3Ni组成，接头剪切强度仅为21.2 MPa。Zn箔的添加促进铝母材溶解，增加Al3Ni的数量并形成Zn-Al共晶，提高2024合金一侧的连接强度。Al箔的填入降低AZ31合金的溶蚀，并在镁合金侧形成MgZn2、MgZn和含有Mg2Ni、Al3Ni、AlMg4Zn11和NiZn8的混合IMCs层的组织，提高AZ31合金与Ni箔的连接。
关键字: Ni/Al/Zn复合钎料层；AZ31/2024；异种金属钎焊接头；超声；瞬间液相扩散焊；复合钎料层；力学性能
（1. School of Mechanical and Automotive Engineering, Qingdao University of Technology, Qingdao 266520, China;
2. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China）
Abstract:By using the Ni/Al/Zn multi-interlayers, the high mechanical performance AZ31/2024 dissimilar alloys joints were made via ultrasonic-assisted transient liquid phase bonding (U-TLP) in air without any fluxes. The microstructure and mechanical performance of the joints were researched by using different set-up of multi-interlayers such as Ni, Ni/Zn, Zn/Ni/Zn and Al/Zn/Ni/Zn. The function of the Ni, Al and Zn foil acted during U-TLP was analyzed. The results show that the phases in the joints can be controlled and mechanical performance of the joints can be improved by adjusting the set-up of the multi-interlayers. The Al/Zn/Ni/Zn interlayers combination significantly increases the shear strength up to 95.3 MPa. The Ni foil, which acts as “physical barrier”, prohibits the formation of Mg-Al intermetallic compounds, however, the shear strength is only 21.2 MPa, which is caused by that the joints at 2024 alloys side is only composed of Al3Ni. The Zn foil accelerates the dissolution of Al atom and increases the amount of Al3Ni. In addition, Zn-Al eutectics are formed and improve the joining between the Ni foil and 2024 alloys. The Al foil, whose aim is to slow down the dissolution of AZ31 alloys, helps to form a IMCs layer of mixture that is composed of Mg2Ni, Al3Ni, AlMg4Zn11 and NiZn8 along the Ni foil and enhance the bonding between Ni foil and AZ31.
Key words: Ni/Al/Zn multi-interlayer; AZ31/2024; dissimilar alloy brazing joints; ultrasonic; transient liquid phase bonding; multi-interlayer; mechanical performance
