Solid state quasi-equal strength repairing for welding defects of 2195 Al-Li alloys

Aiming at the keyhole defects after friction stir welding（FSW） of 2195 Al-Li alloys, the solid state quasi-equal strength repairing based on filling friction stir welding（FFSW） was performed. This method was characterized by low heat input, sufficient friction and material flow and high strength of interfacial bonding. The results showed that introducing the additional filling stud could make the sufficient filling of the keyhole, while the friction stir processing was beneficial to the second forging effects on the repairing regions. By optimizing the welding parameters, when the rotating velocity was 1 600 r/min, the tensile strength of the repaired joint was 358. 1 MPa, up to 90. 7% that of high quality FSW joint, while its elongation was 3. 17%, up to 90. 6% that of high quality FSW joint. It realized the solid state quasi-equal strength repairing of 2195 Al-Li alloys.