铝合金点焊电极端面铜铝合金化热物理模拟

Physical simulation of Cu/Al alloying in aluminum alloy spot welding electrode tip

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。

For the problem of electrode burning loss and low life appeared in aluminum alloy resistance spot welding,based on analyzing of structural constituent and performance by physical simulation,the mechanism of Cu/Al interaction was investigated through the reaction conditions and reaction behavior between the copper electrode and aluminum alloy sheet. The results show that the main reason to decrease electrode life is the alloying interaction between the copper-electrode and aluminum-alloy part. Meanwhile,it is found that the reaction products with Cu9Al4 and Cu Al2 appear at the end surface of an aluminum sample. Then,the intermetallic compound Cu9Al4 and Cu Al2 appear forms at the end surface of an copper sample too,copper and aluminum diffusion layer’s hardness is higher than the copper matrix and aluminum substrate.