TIG电弧预热辅助铝-铜超声波缝焊工艺研究

对1 mm厚铝-铜TIG电弧预热辅助超声波缝焊试验进行了研究，通过金相显微镜、扫描电子显微镜、能谱分析等技术分析了不同TIG电流对焊缝成形、界面温升、界面形貌以及力学性能的影响。结果表明，TIG电弧预热可以软化板材，有助于高频振动能量的传递，为得到良好的缝焊接头提供条件。在TIG电弧预热和纯铝夹层的共同作用下，界面处温度最高可达446℃。当TIG电流较小时，电弧预热不充分，焊接界面处起伏比较平缓，局部区域出现未连接现象，拉剪试件在铝铜界面处断裂；当TIG电流增大到30 A时，在电弧热和高利用率的高频振动能的作用下，界面塑性流动程度提高，界面处出现"嵌合"、"连续凸起"等典型形貌，EDS分析显示界面未出现金属间化合物，拉剪试件断裂在紫铜母材上，最大拉剪力为2.58 kN。

Study on TIG Arc Preheating Auxiliary Aluminum-copper Ultrasonic Seam Welding

TIG arc preheating welding assisted with ultrasonic seam welding experiment are carried out based on a 1 mm thick aluminum-copper. The influences of different TIG currents on the weld formation, interface temperature rise, interface morphology and mechanical properties are analyzed by metallscope, SEM, EDS. The results show that preheating of TIG arc can soften the plate, which facilitates the transmission of high frequency vibration energy, and provide the formation of fine seam welding joint. Under the combined effects of TIG arc preheating and pure aluminum interlayer, the temperature of the interface reaches up to 446℃. TIG preheating is insufficient When current is small. And the welding interface is flat. Not bonded completely. The tensile shear specimen breaks at the aluminum-copper interface. When the TIG current increases to 30 A, the interface plastic fluidity increased, as the result of arc heat and high utilization rate and frequency vibrational energy, the interface exhibits "chimeric", "continuous bulge" and other typical morphologies. EDS analysis shows that the intermetallic compounds did not form at the interface. The tensile shear specimen broke on the copper base metal and the maximum tensile shear force is 2.58 kN.