No.2（2007）12.Resistance Spot Welding of Titanium to Magnesium using Aluminum and Zirconium Insert Metals

Masayuki Aonuma

This paper deals with resistance spot weldability of pure titanium to pure magnesium plates using aluminum and zirconium insert metals. Materials used in resistance spot welding were a 0.8 mm thick magnesium plate and a 0.6 mm thick titanium plate. The effect of an insert metal, which was put into the bonding interface, on the joint strength was examined. Tensile shear test and peel test were done at an as-welded condition. In Ti/Al/Mg joints using aluminum insert metal, the Al-Mg intermetallic compound layer was formed on the interface and the strength of these joints was remarkably low. In Ti/Zr/Mg joints using zirconium insert metal, the Ti-Zr intermediate layer was formed on the Ti/Zr interface and the joining area at Mg/Zr interface was larger than those of Ti/Mg direct joints under equal welding conditions. The intermetallic compound layer was not observed on the interface by a scanning electron microscope. Consequently the strength of Ti/Zr/Mg joints was much higher than those of Ti/Mg joints. This suggests that using zirconium insert metal was effective for increasing the joint strength.

Keywords

resistance spot welding, pure titanium, pure magnesium, dissimilar metal joining, insert metal

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