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.