Rapidly solidified powder metallurgy Al-Si-3%Cu-1%Mg alloy (20, 25, 30%Si) were jointed by friction welding. Regardless of the silicon content, the tensile strength of welded joints were lower than those of the base metals. Elongation of welded joints of Al-30%Si-3%Cu-1%Mg alloy was nearly equal to that of the base metal. On the other hand, those of Al-20%Si-3%Cu-1%Mg and Al-25%Si-3%Cu-1%Mg alloys were slightly lower. All the friction welded joints were fractured at the weld interface. As for the heat affected zone, the hardness increased in a narrower range than that of the base metal while in the position 4mm distance from the weld interface. The original fibrous structures were pressed forward to the outside along the flux of burr on the heat affected zone by the heat and axial pressure at the welding process, while they disappeared near the weld interface, and welded layer formed at the weld interface.
