Microstructure and mechanical properties of linear friction welding joint of TC17 titanium alloy fabricated by laser forming

Under the background of repairing damaged blades of blisks with linear friction welding, aimed at TC17 titanium alloy which is commonly used for aero-engine blades, one of the welding stub is fabricated by laser forming, microstructure analysis, mechanical properties test and fracture analysis of typical welded joints were carried out, the evolution characteristics of the laser deposition zone before and after linear friction welding and its influence on mechanical properties were emphatically analyzed. Results showed that the size of shortening determines the amount of laser forming structures in the joint, obvious recrystallization occurs in the laser forming deposition zone which participated in the welding process, the original coarse grains were broken and small α phases were precipitated inside the grains. the tensile properties of the three typical joints are equal to that of the base metal, when the structure of deposition zone is removed in linear friction welding process, the high cycle fatigue strength of the joint can reach more than 90% of that of the base metal.