Laser Roll Welding of Dissimilar Metal Joint of Titanium to Aluminum Alloy

Recently, the demands of dissimilar metal joint of titanium to aluminum alloy have been arisen in industries, especially in transportation vehicle industry. However, it is well known that fusion welding of titanium to aluminum alloy is difficult because of generating the brittle intermetallic compound at the joint interface. Therefore, new welding processes with high reliability and productivity for these dissimilar materials are demanded. In the present work, Laser Roll Welding of titanium to aluminum alloy using a 2 kW fiber laser was tried to investigate the effects of the process parameters on the formation of interlayer and the mechanical properties of the joint. As a result, the cross-section of joint shows partial melting of the aluminum sheet and spreading of molten aluminum alloy on the titanium sheet occurs during the welding thermal cycle. Various types of intermetallic compound were confirmed at the interlayer of welded joint. The specimen with a bonding width of 2.8 mm was failure in the base metal of titanium in the tensile shear test. In Erichsen cupping tests, Erichsen value was 5.7 mm. This value was 89% of the base metal of aluminum sheet.