Effect of inoculants Ti and Zr on microstructure and mechanical properties of 2219 Al-Cu alloy welding

Metal inert gas(MIG) welding was used to weld 2219 Al-Cu alloy with five kinds of filler metal, effect of the inoculants Ti and Zr additions in filler wires on the microstructures and properties of weld metal was investigated.The results showed that Ti and Zr was compatible, grain structures of weld were coarse columnar grains with a little Ti or Zr in filler wires, Al₃Ti and Al₃Zr were formed in the welding pool with additions of a little Ti and Zr in filler wires, which provided the heterogeneous nucleation sites for α(Al).The grain of the microstructure of weld metal was finer with the increasing of Ti and Zr compositions in filler wires.Intermetallic aluminized dispersoids Al₃(Ti, Zr) were formed in weld metal with additions of large amounts of Ti and Zr in filler wires, which accelerated the heterogeneous nucleation of α(Al) and resulted in refining grains of the weld metal, so the tensile strength and elongation of weld joint were increased.