Solid-State Repair of Casting Defects in ZL210 Aluminum Alloy

Casting defects in the ZL210 aluminum alloys were repaired via a solid-state welding method named active-passive filling friction stir repairing (A-PFFSR). Effects of plunge speed on microstructures and mechanical properties of repaired joints were investigated based on a six-spiral-groove pinless tool. Casting defects were firstly machined into a tapered hole by a tapered and threaded pin. Then, the keyhole was successfully repaired by the materials surrounding the keyhole and an extra filler via the A-PFFSR. The lower plunge speed was propitious to improving frictional heat and material flow, which improved joint integrity containing surface appearance and interface joining behaviors. The maximum tensile strength of the repaired joint was approximately equivalent to that of base ZL210 alloys, realizing the quasi-repairing of the ZL210 aluminum alloys.