铝—铜异种金属连接接头的组织及导电性研究

发布时间：2018-06-19 09:33

本文选题：固-液复合连接 + 脉冲旁路耦合MIG电弧焊　；参考：《兰州理工大学》2017年硕士论文

【摘要】：本文针对不同的铝铜连接方式在不同的试验参数下获得的铝铜接头的组织及导电性之间的问题进行研究。采用固-液复合连接的方法选用1060铝板以及T2铜板获得铝铜复合接头,采用脉冲旁路耦合MIG焊的方法选用ER4043、ER4047以及ER1100焊丝在不同的试验参数下获得铝铜焊接接头。在对不同连接方式接头的界面进行分析的过程中发现接头界面的组织及导电性存在很大的差异。对于固-液复合连接的接头来说,原子间的扩散更加的充分,结合更加紧密,接头的成分更加趋近于平衡条件下铝铜之间的反应。在对铝铜界面进行分析时发现在一定温度保温时铝铜界面微观组织的生长形貌比较平整。当扩散的能量足够充分时,铝铜界面的生成物含量以及种类逐渐的增加。根据前期工作,采用脉冲旁路耦合MIG电弧焊的接头进行导电性分析的过程中发现焊接后用纯铝焊丝接头的导电性小于硅系焊丝接头的导电性,就此问题对接头的界面进行分析,当焊丝中含有硅元素时会增加接头的焊接性,增加接头连接的紧密性。在对3种不同类型的接头的界面进行分析时发现1100焊丝界面的金属间化合物层的厚度要大于4043以及4047焊丝接头的金属间化合物层的厚度,4047焊丝接头相对于4043焊丝接头的金属间化合物的厚度要薄,说明在硅元素含量一定时对接头金属间化合物的生长具有一定的抑制作用。在对焊接接头进行热处理的过程中发现接头的形貌及成分会发生变化,尤其是在热处理温度为共晶温度时,CuAl2相的形貌由热处理前的块状变为枝晶状,并且在CuAl2相的枝晶间以及枝晶前端析出大量的硅元素。分析不同连接方式的接头时发现接头会随着热量以及作用时间的变化产生不同的金属间化合物层,由于焊接热源的特殊性,在焊接接头界面产生的金属间化合物相有CuAl、CuAl2以及CuAl2的共晶组织,但根据已有的理论Cu9Al4是紧随CuAl2产生的第二相,而对焊接接头检测没有Cu9Al4,因此可以推断物相的生成在满足条件后仍然需要一定的孕育时间。对不同连接方式下的接头的导电性进行分析时发现接头的导电性随着金属间化合物层的厚度的增加而减少,并且当过渡层在持续及单一的情况下时,接头的导电性较好。
[Abstract]:In this paper, the structure and electrical conductivity of Al-Cu joints obtained by different Al-Cu bonding methods under different test parameters are studied. Aluminum-copper composite joints were obtained by solid-liquid composite bonding with 1060 aluminum sheet and T2 copper plate, ER4043 and ER4047 and ER1100 wires were used to obtain Al-Cu welding joints under different test parameters by pulse by-pass coupling MIG welding. In the process of analyzing the interface of different joints, it is found that there are great differences in the structure and conductivity of the joints. For the solid-liquid composite joints, the diffusion between atoms is more sufficient and the bonding is closer, and the composition of the joints is closer to the reaction between aluminum and copper under equilibrium conditions. It is found that the microstructure of Al-Cu interface is smooth when the Al-Cu interface is heated at a certain temperature. When the diffusion energy is sufficient, the product content and species of Al-Cu interface increase gradually. According to the previous work, the electrical conductivity analysis of MIG arc welding joints with pulse bypass coupling shows that the electrical conductivity of pure aluminum welding wire joints after welding is smaller than that of silicon wire joints. The interface of the joints is analyzed in this paper. When the wire contains silicon, the weldability and tightness of the joint will be increased. The intermetallic layer thickness of 1100 wire interface is greater than that of 4043 wire joint and 4047 wire joint. The thickness of 4047 wire joint is relative to 4043 wire. The intermetallics of the joint are thin in thickness, The results show that the growth of intermetallic compounds can be inhibited when the content of silicon is constant. During heat treatment of welded joints, it was found that the morphology and composition of the joints would change, especially when the heat treatment temperature was eutectic, the morphology of CuAl2 phase changed from bulk to dendritic before heat treatment. And a large amount of silicon elements are precipitated between the dendrites and the front end of the CuAl2 phase. It is found that different intermetallic compound layers will be produced with the change of heat and action time, because of the particularity of welding heat source, because of the particularity of welding heat source. The intermetallic compound phase produced at the interface of welded joints consists of CuAlAl2 and CuAl2 eutectic structure, but according to the existing theory, Cu9Al4 is the second phase following CuAl2. However, there is no Cu9Al4 for welding joint detection, so it can be inferred that the phase formation still needs a certain incubation time after satisfying the conditions. It is found that the conductivity of the joint decreases with the increase of the intermetallic layer thickness, and when the transition layer is continuous and single, the conductivity of the joint is better.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG407

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