Abstract:

Two kinds of graphite are brazed to copper alloy by Ag-Cu-Ti liquid solder via vacuum brazing technology. Experiments are conducted to investigate the influence of brazing temperature, intermediate layer and the size of bases on property of joints. Shear strength of joints are tested via self-designed mold by tensile testing machine. Microstructure characteristics and phase composition are observed and analyzed by scanning electron microscope and the build-in energy dispersive X-ray analysis. Experiment results reveal that continuous and tight joint interface organization of graphite/copper alloy is obtained in the condition of 910℃ brazing temperature holding for 10 minutes. Compared with GA graphite, joints of Artech graphite/copper alloy have higher shear strength. When oxygen-free copper of 1mm is used as the intermediate buffer layer, the brazing thermal stress can be effectively relieved and the joint strength can be significantly improved.

Key words: Ag-Cu-Ti paste solder, Vacuum brazing, Graphite, Copper alloy, Shear strength

摘要：

利用银铜钛(Ag-Cu-Ti)膏状钎料采用真空钎焊的方法对两种不同石墨和铜合金进行钎焊连接实验，研究了钎焊温度、中间缓冲层、母材尺寸等工艺参数对接头性能的影响。采用自行设计模具对接头的剪切强度进行了测试，利用扫描电镜和配带的X射线能谱分析仪分析了接头界面组织形貌及元素物相成分。研究结果表明：当钎焊温度为910℃，保温时间10min时，Ag-Cu-Ti膏状钎料能够与石墨和无氧铜两侧母材形成良好的结合界面；与GA石墨相比，阿泰克石墨与无氧铜接头强度更高；采用1mm无氧铜做中间缓冲层钎焊石墨和铬锆铜时，能有效缓解钎焊热应力，接头强度有明显提高。

关键词: 银铜钛(Ag-Cu-Ti)膏状钎料, 真空钎焊, 石墨, 铜合金, 剪切强度