Physical simulation of alloying between copper and aluminum on electrode tip for resistance spot welding of 5A02 aluminum alloy

The applicatio, n of aluminum alloy in the automotive and aviation fields is impeded by the wear and life of electrode for resistance spot welding （RSW）. The alloying interaction between the copper electrode and aluminum alloy sheet is the main reason of making electrode life decrease. The test of alloying interaction is difficult because of the transient in RSW of aluminum alloy. In this paper, the process of alloying between copper and aluminum on the electrode tip is simulated with Gleeble-1500 thermal simulation testing machine. The microstructure and composition of the sample of physical simulation for the alloying interaction between the copper electrode and aluminum alloy are analyzed using scanning electron microscope （SEM） and X-ray diffraction （XRD） respectively. The results indicate that the alloying reaction between copper and aluminum under the different temperature, pressure and time is mainly the eutectic reaction. The reaction result is the eutectic of （ Al ＋ CuAl2 ） , and then Cu9Al4 forms through solid diffusion between the CuAl2 phase and the copper base metal.

铝合金点焊电极端面铜铝合金化热物理模拟

针对铝合金电阻点焊过程中出现的电极烧损及使用寿命短的问题,采用物理热模拟的方法,从点焊电极端面铜铝合金化的组织、成分和性能等方面进行了铝合金点焊电极端面铜铝合金化反应的行为和条件研究。研究结果表明:电极端面与工件接触界面发生铜铝合金化反应是铝合金点焊电极烧损的主要原因;铝试样端面生成了C u Al4和C u Al2,铜试样端面主要是C u Al2和少量的C u9Al4,且铜铝扩散层的硬度高于铜基体和铝基体。