超声波辅助钎焊铜与石墨的组织及性能

Structure of ultrasonic assisted brazing of copper with graphite and its performance

采用四元合金Ag30Cu25Zn4Ti作为活性钎料,在大气中利用超声波辅助钎焊技术对铜和石墨进行了钎焊.通过改变超声波作用时间和方式,研究了不同超声波作用时间下钎料氧化膜破碎的效果,及其与TiC反应层形貌之间的关系.采用扫描电子显微镜对钎焊接头的微观组织进行了观察,最后对钎焊的接头进行了力学性能分析.结果表明:随着超声波作用时间的延长,液态钎料中的氧化膜逐渐减少,最终完全消除;与此同时,TiC反应层的厚度也在逐渐增加,最终趋于稳定.钎焊接头的组织由铜侧到石墨侧依次主要为Cu/Cu-Zn金属间化合物,Ag基固溶体和Cu基固溶体/TiC/石墨,钎焊接头的剪切强度最大值为18 MPa,界面的结合主要是超声波作用下活性元素Ti在石墨侧的偏聚形成TiC反应层而形成的.

Taking tetradie alloy Ag30Cu25Zn4Ti as active filler metal, the brazing of copper with graphite was carried out by using ultrasonic assisted brazing technology in atmosphere. By changing the ultrasonic action time, the relationship of the crushing effect of solder oxidation film and the morphology of TiC reaction layer to the ultrasonic action time is investigated and the scanning electron microscopy is used to analyze the microstructure of brazing joint. Then, the mechanical properties of brazing joint are analyzed. The result, showed that with the prolonging of the ultrasonic action time, the oxidation film in the liquid solder will decrease gradually until complete elimination. At the same time, the thickness of the TiC reaction layer will gradually increase, and finally tends to be stable. The microstructure of the brazing joint will he composed, from copper side to graphite side, mainly of ordered Cu, Cu-Zn intermetallic compound, Ag-based solid solution, Cu-based solid solution, TiC and graphite, The maximum shear strength of brazing joint can amount to 18 MPa. The combination of high strength interdace will mainly be formed by the formation of TiC reaction layer due to the off-segregation of active element Ti on the graphite side.