For developing high conductivity and high strength aluminum alloys for electrical application, the effects of alloying elements on electrical conductivity and tensile properities of Al-Ni-Mg-B alloys were investigated. Aluminum alloys were produced by wire fabrication process consisting of casting, reheating, hot extrusion and cold drawing. Ni was least detrimental to the electrical conductivity and increased the tensile strength of Al alloys by the formation of eutectic NiAl₃. Addition of B to Al-Ni-Mg alloys increased the amount of eutectic NiAl₃ and the electrical conductivity. The electrical conductivity of Al-Ni-Mg-B alloys was increased by the precipitation of Ni-Al intermetallic compounds during hot extrusion. Addition of Mg to Al-Ni alloys increased the resistance to softening. (Received February 2, 1999)