Static and Fatigue Characterization of Titanium Alloy Welded Joints

Titanium and its alloys presents an elevated strength/weight ratio, good mechanical properties at high temperatures, elevated resistance to corrosion and to most part of acid attacks. These characteristics, thanks to recent improvements in welding techniques that allow the realization of high quality welded joints, makes this material attractive for numerous applications. Naval industry, for which the corrosion constitutes a discriminating element in the choice of materials, is studying new applications for the titanium. Fatigue strength of titanium alloys is the most important information needed for naval structural applications, but none official standard similar to Eurocode exists and data available in literature are still not sufficient for a reliable fatigue design. This work is focused on the study of static and fatigue behavior of butt welded joints in titanium grade 2 and grade 5, all obtained by laser welding technique. The experimental results of fatigue tests are presented both in terms of nominal stress amplitude σa and local strain amplitude εa.