Zn-Al钎料固相率及组分对Cu/Al管磁脉冲-半固态复合辅助钎焊接头质量的影响初探

由于节能环保以及轻量化的要求,Cu/Al异种金属复合管件被广泛应用于各工业领域,为此探索一种Cu/Al管件间高效可靠的连接技术具有较大应用价值和研究意义。为了探究Cu/Al管半固态钎焊连接机理并优化相关工艺参数,基于新提出的磁脉冲-半固态复合辅助钎焊方法制备了Cu/Al异种金属管件钎焊接头,利用LS-DYNA分析了半固态钎料不同表观粘度参数下外管内壁的受力情况,采用材料力学拉伸试验机,能谱仪和电子探针显微分析仪研究了半固态Zn-Al系钎料固相率及组分对焊接接头质量的影响。结果表明:外管内壁所受压力幅值随着表观粘度的增大而减小,剪切应力随着表观粘度的增大而增大；半固态钎料固相率为0.8时钎料与母材间没有良好冶金结合,固相率为0.4时会导致钎料填充不足的缺陷。在二次放电电压7 kV,半固态Zn-Al钎料固相率为0.6的条件下,磁脉冲-半固态复合辅助钎焊工艺能够实现Cu/Al管的无钎剂有效连接；与Zn-3Al和Zn-22Al相比,Zn-15Al钎料制得的接头综合性能更好,是较为合适的Cu/Al管磁脉冲辅助半固态钎焊用Zn-Al钎料。

Preliminary study on the influence of solder solid phase rate and composition of Zn-Al filler metal on the quality of magnetic pulse-semisolid hybrid assisted soldering of Cu/Al tubes

Due to the requirements of energy saving, environmental protection and light weight, Cu/Al tubes are widely used in various industrial fields. Therefore, it is of great application value and research significance to explore a highly efficient and reliable joining technology between Cu/Al tubes. In order to explore the joint mechanism of magnetic pulse-semisolid hybrid assisted soldering of Cu/Al tubes and optimize the process parameters, Cu/Al dissimilar metal tubes joints was prepared by means of the new method of magnetic pulse-semisolid hybrid assisted soldering, the stress of the inner wall of the outer tube under different apparent viscosity parameters of semi-solid Zn-Al solder was analyzed based on LS-DYNA.The influence of solid state ratio and composition of semi-solid Zn-Al system solder on the quality of welded joint was studied by means of material mechanics tensile tester, energy dispersive spectrometer and electron probe microanalyzer. The results show that the pressure amplitude of the inner wall of the outer tube decreases with the increase of apparent viscosity, and the shear stress rises with the increase of apparent viscosity. When the solid phase ratio of the semi-solid brazing filler metal is 0.8, there is no good metallurgical bond between the brazing filler metal and the base metal, and the solid phase ratio of 0.4 causes defects in insufficient filler filling of the brazing filler metal. Under the condition of secondary discharge voltage of 7 kV and semisolid Zn-Al solder solids phase ratio of 0.6, the magnetic pulse-semisolid hybrid assisted soldering process can realize the effective connection of Cu/Al pipe without flux; compared with Zn-3Al and Zn-22Al, the joint made of Zn-15Al solder has better comprehensive performance and is a more suitable Zn-Al solder for Cu/Al magnetic pulse-semisolid hybrid assisted soldering.