Stress relaxation of electrical conductor aluminium

Abstract

Stress relaxation and creep at room temperature were studied in electrical conductor aluminium wire. In hard-drawn aluminium the stress relaxed at about the same rate, or jaster, as in annealed aluminium, in spite of the yield strength and the creep strength being greater in the cold-worked state. The contradiction in this is only apparent. The poor stress relaxation properties of the hard-drawn material can be explained by the unusually low stress-dependence of creep in this condition. The properties of the cold-worked wire were markedly anisotropic. Compression in the transverse direction produced much faster stress relaxation than compression in the longitudinal direction. By a recovery anneal the poor properties of the hard-drawn material in the transverse direction could be improved to the level of the annealed material with hardly any reduction in yield strength.