Welding repair by linear friction in titanium alloys

Gas turbines for aeroengines are generally manufactured by attaching individual blades into slots in the disk. However, an alternative design consists in producing bladed disks, where disk and blades are a single piece. Previous studies have shown that linear friction welding is a technology which fits well for this application. On the other hand, bladed disks can experience in service damages and therefore affordable repair technology must be available. The present paper presents the microstructural and mechanical evaluation of double and triple welds produced to simulate replacements of damaged blades. The results show that, even though the successive welds induce a small strength decrease, both tensile and fatigue failures always initiated far away of the weld zone.