Al接触共晶反应钎焊接头形成过程和机理

PROCESS AND MECHANISM OF Al EUTECTIC CONTACTING REACTION BRAZING

用电子探针和扫描电镜分析了Al接触共晶反应钎焊接头的形成过程和机理。Al接触共晶反应钎焊反应层形成过程可分为 3个阶段 :①原子之间的扩散和溶解。②成分均匀化。③反应层的等温凝固。Cu原子可以沿Al的晶界优先扩散 ,达到共晶成分后形成液相 ,实现Al的接触共晶反应钎焊。

Process and mechanism of aluminum eutectic contacting reaction brazing is studied by using a scanning electron microscope and an electron probe.The formation process of the eutectic reaction layer can be divided into three stage:the first is the diffusion and dissolution between atoms;the second is the composition homogenization;the third is isothermic solidification of the eutectic reaction layer.The results show that the Cu on the grain boundary of base metal Al must come from the solid atoms through diffusion of the Cu.After the eutectic ingredients is accumulated a binary low melting point eutectic substance is formed at the grain boundary.The eutectic reaction brazing of Al is formed.