Saldatura ibrida laser-MIG di giunti a T in lega di titanio

Innovation in materials and joining processes continues to play a key role in the evolution of the transport sector, in general, and in the aviation in particular. Important factors of innovation are the improvement in ntaterial and processes performances, coupled to the associated cost reduction. Titanium alloys, characterized by high mechanical properties and corrosion resistance, are particularly interesting for the aeronautical sector Their joining, from metal sheets with equal or different thicknesses, is mainly carried out by using laser or arc welding techniques. With the laser process, a high amount of energy is applied in a very limited area for a very short time, resulting in a reduced heat affected zone. With the arc welding, a large amount of heat is applied in a larger area for a longer time, obtaining a more extended heat affected zone. The combination of the process with high energy density (laser) with the high energy contribute (MIG) has been shown to enhance the beneficial effects of both processes (key-hole, ability to bridge sheet gap) while limiting their drawbacks (high thermal gradient, low mechanical resistance). In this paper, the hybrid Laser-MIG welding ofTi-6Al-4V was investigated. The welded joints were obtained from with 3-mm thick sheets using the double fillet welded Tjoint. The main factors of evaluation were the morphology of the weld bead and energetic considerations