薄壁铜铝管电阻焊焊接界面的微观结构研究

Microstructure investigation for the interface of electric resistance welded Cu/Al thin walled tube

利用SEM、EDS等技术对电阻焊薄壁铜铝管焊接界面进行研究,并结合Cu-Al二元相图进行界面分析。研究结果表明在铜铝连接管的焊接界面处,铜与铝进行原子的互扩散,且铜原子向铝侧扩散的深度比铝原子向铜侧扩散的深度要大。对界面进行背散射电子分析和能谱分析,发现界面存在柱状晶形貌的CuAl2相和呈灰白相间的层片状的α-Al与CuAl2的共晶。讨论柱状晶与共晶组织的形成与性能,并分析其对接头性能的影响。

Scanning electron microscope （SEM） and energy-dispersive spectroscopy （EDS） and other analytic techniques were used to study the characteristic of the interface of the electric resistance welded Cu/Al thin walled tube in this paper. The interface was analyzed according to the Al-Cu binary phase diagram. It＇s found that a certain interdiffusion of aluminum and copper took place in the welding interface of the Cu/Al tube and the diffusion was primarily one way from the Cu side into the Al side. Furthermore, the interface region of Cu/Al was examined by BEI and scanning electron microscope and EDX analyzer and found that it consisted of columnar crystals of CuAl2 and the eutectic of α-Al/CuAl2 with the morphology of alternative α-Al/ CuAl2 lamellae. The phases present in the welds were explained and the relationship between the properties of joints and the morphology was also discussed.