Aluminum Alloy Soldering Procedure Research Based On The Sn-Pb-Zn Solder

A Sn-Pb-Zn low temperature solder was developed and a soldering procedure of 6061 aluminum alloy under 300℃assisting with the ultrasonic was researched by the dissertation.Alloying method was used to improve the traditional eutectic solder. On the basis of Sn-Pb solder, a new solder with Sn, Pb, Zn as basic ingredients, Ag, Cu, Bi as addition elements was developed. DSC experiment shows that the liquidus temperature of the new solder is 190.7℃, which is closed to that of the traditional Sn-Pb eutectic solder, 183℃. The wetting tests from 250 to 280℃shows that the solder has good spreading performance on the 6061 aluminum alloy under 300℃.The ultrasonic cavitation can be used to remove the oxide film on the aluminum alloy and coat the solder to the treated surface of aluminum alloy at the same time. Ultrasonic assisting dip soldering without flux and argon gas furnace soldering with pre-coating solder with ultrasonic were done to the 6061 aluminum alloy under 300℃. Shear strength tests were done to the soldered joints and the shear fractures were analyzed by the Scanning Electron Microscope (SEM). Metallographic, SEM and Energy Dispersive Analysis of X-rays (EDAX) analysis were done to the joint seams. Shear strength tests shows that the shear strength of the ultrasonic assisting dip soldered joints is higher than 45MPa and that of the argon gas furnace soldered joints is above 20MPa. Joint shear fracture analysis shows that the fracture belonged to tenacity fracture. Metallographic and SEM observation of the soldered joint seams shows that the soldering interfaces are well connected and filler layers are made up of different phases. EDAX reveals that the phases are Sn rich solid solution, Pb rich solid solution and near Sn-Pb eutectic phase. Electron-Prode Micro Analysis (EPMA) line scanning results of the solder joint seam show that a diffusion layer is formed between the solder and the Al alloy matrix and thickness of the layer is about 1 to 2 microns. Ultrasonic assisting dip soldering tests were done to the aluminum sandwich panels. Through metallographic micro observation, the joints are connected well. The research results provide a reliable theoretical guide for soldering aluminum sandwich panels.