Fatigue behavior of hybrid Ti6Al4V cruciform welded joints

This paper presents experimental fatigue results of titanium grade 5 (Ti6Al4V alloy) cruciform welded joints. The joining process used to realize the joints is the hybrid CO2 laser-MIG welding technique. In this technique the laser beam is combined to the MIG arc in order to have advantages from both processes. The fatigue curves expressed in terms of nominal amplitude of stress (according to the traditional global method) and in terms of local amplitude of strain (according to the local Wel.Fa.Re. method) have been plotted after the experimental tests. Electrical strain gauges bonded close to the weld toe have been used to calculate the local strain amplitude. The fatigue tests have been carried out applying an axial loading to the specimen with a load ratio of 0.1. Finally a comparison with the fatigue resistance of hybrid butt welded joints is presented.