镁合金电阻点焊焊接性研究  

Weldability of magnesium alloy by resistance spot welding

作　　者：郎波[1] 马金瑞[1] 孙大千[2] 乔健[3] 

机构地区：[1]北京航空制造工程研究所,100024 [2]吉林大学材料科学与工程学院,长春市130025 [3]中国科学院长春光学精密机械与物理研究所,130033

出　　处：《焊接》2010年第4期24-29,共6页Welding & Joining

基　　金：吉林省科技发展计划(20070309)

摘　　要：为了提高镁合金电阻点焊接头的力学性能,采用扫描电镜和能谱仪研究了电极烧损和焊接缺陷的形貌及形成机理。结果表明,点焊过程中熔化的镁合金与电极粘在一起并发生反应,而形成局部的、复杂的Cu-Mg合金化区域,从而导致电极烧损。结晶裂纹的形成主要与Al和Mn元素偏析造成的晶间低熔点液态薄膜和拉伸应力有关。液化裂纹的形成主要与溶质偏析形成的低熔点液化膜和拉伸应力有关。内部喷溅主要与接头加热速度过快有关,而外部喷溅主要与工件和电极端面接触不良有关。如果有效的电极压力不足,点焊结束后将在熔核中形成缩孔。In order to improve the mechanical properties of magnesium alloy joint welding by resistance spot welding, morphology and formation mechanism of electrode degradation and weld defects had been investigated by scanning electron microscopy (SEM) and energy-dispersive spectrum (EDS). The studied results show that the molten magnesium alloy adheres to and reacts with the electrode to form local and complex regions of Cu-Mg alloys during welding, which results in the electrode degradation. The formation of solidification cracking is related to low melting point liquid films between dendrites due to segregation of Al and Mn element and tensile stress. The formation of liquation cracking is mainly associated with low melting point liquid films from solute segregation and tensile stress. Internal and external expulsion are mainly related to rapid rate of heat input in the joint and poor contact of workpiece and electrode tip face, respectively. If the effective electrode force is not enough, shrinkage cavity will form in the weld nugget after welding.

关 键 词：镁合金 电阻点焊电极烧损焊接缺陷 

分 类 号：TG452.9[金属学及工艺—焊接]