Effect of Small Additions of Fe on the Tensile Properties and Electrical Conductivity of Aluminium Wires

Although low-alloyed aluminum has been used as electric line and cable materials to date, there still is a great demand for higher strength with retaining the good electrical conductivity and ductility. In the study, iron has been chosen as an additive element and the addition effect on the strength and electrical has been investigated since iron is reported to have a marked solution-strengthening effect at a given addition amount. Aluminum with 99.99mass% purity and Al-Fe alloys with iron up to 0.9mass% were induction-melted, continuously cast into a rod with 8mm diameter, and cold-drawn into a wire with 0.3mm diameter. Tensile test and electrical resistivity measurement were carried out on the rod and wire after each pass. It was found that, in the rod, the strength increased while the ductility and electrical conductivity decreased as the addition iron amount was increased. Work hardening occurred clearly at an early stage of cold drawing, while it became sluggish as the cold reduction increased in each material. At the early stage, the strengths increased as the iron amount was increased, and at the later stage, the alloy with iron addition of 0.9mass% had higher strengths and larger elongation to failure.