National Research Council of Canada. NRC Institute for Aerospace Research
ICALEO 2009, International Congress on Applications od Lasers and Electro-Optics, November 2-5, 2009, Orlando, USA
Conventionally, TIG, plasma arc, electron beam and CO2 laser welding have been used to join titanium alloys. To date, little has been reported on the weldability of titanium alloys using high power Nd: YAG lasers. This work reports on the effect of joint gap on the characteristics of 3.05-mm thick Ti-6Al-4V alloy welded using a 4 kW Nd: YAG laser. Examination of butt welded Ti-6Al-4V alloy indicated that full penetration is possible up to a joint gap of 0.5 mm. The main defects in the welds consisted of underfill and porosity. The application of filler wire during welding was observed to reduce the underfill defect. The porosity increased with increasing joint gap, although it remained less than 1% of the fusion zone area. The tensile properties seemed optimal at an intermediary gap size (0.2 - 0.3 mm), most likely due to a balance between underfill and porosity defects.