Formability is a key factor which influences the friction weldability of dissimilar materials. Resistance to formability of metals can be reduced by the electric induced plasticity under an external electric field. Friction welding of T2 Copper and 1Cr18Ni9Ti stainless steel was carried out under the electric fields with an attempt to improve the friction welclability of these two materials. Effects of different types of external electric field on the microstructure of the welded joints were investigated and distributions of the dominating elements in the weld zone were analyzed using EDX Torsion strength of the joints obtained from different welding parameters was tested. It was indicated that the dynamic recrystallization of the weld metal was enhanced by the applying electric fields. For the specimen connected to the cathode of the power supply (referring to negative field), much homogenous distribution of the recrystallized grains in the weld zone appeared. The diffusion distance of the dominating elements increased under either an AC electric field or a negative field. The torsion strength of the welding joints was improved with applying the external electric field, especially with the AC electric field. (c) 2006 Springer Science + Business Media, Inc.