Ring-like laser spot welding of Ti grade2 to AAl3105-O using AlSiMg filler metal

A pulsed Nd:YAG laser welding of 1 mm thick Ti (grade 2) to 0.5 mm thick AA3105-O was performed by a ring-like spot joining. A 0.15 mm thick Al-12Si-2.5 Mg alloy was used as a filler metal. Intermetallic compounds of Ti3Al, Ti2Al, TiAl, Ti(Al,Si)(3) and Mg2Si were observed respectively from Ti towards Al sides at the fusion zone. Si and Mg increased the strength of the Al re-solidified zone near the Ti-Al interface because of their easy dissolution in the Al. Exothermic effect of the Mg addition resulted in porosity in the welding zone. Joint strength of up to 98% of the Al base metal was obtained, which was much 14% higher than that achieved by autogenous welding.