Effects of electron beam welding parameters on the microstructure of titanium to aluminum alloy joints

Electron beam welding of titanium alloy to aluminum alloy was carried out by melting and melt-brazing to investigate the effects of welding parameters on microstructure of the joint. The results indicated that the joint of the specimen welded by melting was well-formed but contained a large amount of intermetallic compounds. These intermetallic compounds were mainly composed of brittle phases such as TiAl and TiAl₃ that decreased the ductility of the joints and resulted in a tensile strength 50% lower than that of the base metal. In the melt-brazing experiment, direct heat was applied to the aluminum alloy to melt the aluminum rather than the titanium alloy, creating a well-formed joint. The weld was mainly composed of Al element and only a 3 μm thickness of intermetallic compounds formed near the fusion line at the Ti side. The ductility and the performance of the joint were significantly improved compared with those of the melting-only joint. In addition, the tensile strength of the joint reached 80% of that of the aluminum base metal. Copyright: