Interfacial characteristic and property of Ti/Al dissimilar alloys joint with arc welding-brazing

Ti/Al dissimilar alloys were successfully joined by AlSi5 filler metal and TIG-AC arc,and the joints with the characters welding and brazing were gained.The interfacial microstructure and property of Ti/Al welding brazing joints were analyzed by optical microscope(OM),scanning electron microscopy(SEM),energy dispersive X-ray spectrometer(EDS) and tensile test.The results indicate that interfacial layers exhibit club-shaped,diamond-shaped and coniform-shaped respectively,with welding current changes from 30 A to 60 A.The excessive heat input resulted in oversized column interfacial layer,cold cracks were produced during cooling stage under influence of welding stress.TiAl₃ is the main phase of the interfacial layer,which is a typical supersaturated solid solution of Si element.The strength-current curve exhibits two peak values.The maximum average tensile strength is 103 MPa with welding current of 30 A,while the curve exhibits the second peak value with welding current of 60 A due to the decreasing of arc energy density.