Study of porosity formation during laser welding of TI6AL4V

Lightweight structures for aerospace applications can be achieved by the use of materials with a high strength to weight ratio such as titanium. Laser welding has the advantages as a joining process that that it produces low distortion and can achieve deeper penetration welds than conventional TIG welding. Stringent safety criteria require low porosity inside a weld in order to achieve predictable strength and fatigue behavior over the lifetime of the structure. This paper describes a study conducted to determine the effects of weld process parameters and sample preparation on porosity formation. Weld tests were carried out on 0.063" and 0.25" Ti6Al4V sheets. The weld shape had a significant influence on porosity formation. The titanium weld shape was primarily affected by weld speed and wire feed rate. Thorough cleaning of joints with mechanical removal of oxide layers also led to low porosity levels.