热处理对铜铝低温钎焊的影响

Effect of heat treatment on low temperature brazing of copper and aluminum

研究了热处理温度和保温时间对低温钎焊Al/Sn-Bi/Cu接头强度的影响,采用光学显微镜和扫描电镜对接头界面显微组织和断口表面形貌进行了分析。结果表明,随着热处理温度的增加,焊接件的剪切强度表现出增加的趋势。随着热处理时间的增加,Al/Sn-Bi/Cu接头的剪切强度呈现出先增大后减小的趋势。钎焊时铜铝元素进入到钎焊层当中,主要以Cu-Al固溶体的形式存在,并随着热处理时间延长而聚集。热处理使钎缝内粗大的脆性Sn-Bi共晶组织变得细小且覆盖面积减小,从而增加接头强度,Cu-Al固溶体聚集和生长会降低接头强度。

Effect of heat treatment temperature and holding time on strength of Al/Sn-Bi/Cu joints brazed at low temperature was studied. The microstructure of the joint interface and the fracture surface morphology were analyzed by means of optical microscope and scanning electron microscopy. The results show that with the increase of heat treatment temperature, the shear strength of welded parts shows an increasing trend. With the increase of heat treatment time, the shear strength of Al/Sn-Bi/Cu joints increases first and then decreases. During brazing, copper and aluminum elements enter the brazing layer, mainly exist in the form of Cu-Al solid solution, and accumulate with the prolongation of heat treatment time. Heat treatment makes the coarse and brittle Sn-Bi eutectic structure in the brazing seam finer and reduces the coverage area to increase the strength of the joint. The aggregation and growth of Cu-Al solid solution decrease the strength of the joint.