Investigation Of Mechanical Properties And Conductivity Of Medium-Strength Aluminum Alloys For Energy-Saving Conductors

Medium-strength aluminum alloy is widely used as overhead transmission lines in foreign countries owing to its excellent electrical conductivity and mechanical properties. Unfortunately, there are rare reports on the investigation and the application. In this study, electrical and mechanical properties such as tensile, fatigue and stress relaxation properties were investigated systematically. On the other hand,6060 aluminum alloys subjected to accumulative-rolling and subsequent aging treatment were also investigated. Scanning electron microscopy (SEM), electron back-scattered diffraction(EBSD), transmission electron microscopy (TEM) and X-ray Diffraction (XRD) were used to characterize and analyze microstructures of the alloys.The results show that the as-drawn medium-strength LHA3 aluminum alloy wires exhibits an obvious<111> fiber texture, and the grains became elongated along the tensile direction. Under stress control and the stress ratio of 0.1, the fatigue limit of the alloy is 136 MPa, the coefficient and the index of fatigue strength are σf-237 MPa and b=-0.07479, respectively. The relationship between cyclic relaxation stress and the fatigue lifetime of the LHA3 medium-strength aluminum alloy wires was obtained, and the service lifetime of the wires in the process of cycle stress relaxation was evaluated.The 6060 aluminum alloy after accumulative-rolling and aging exhibited the texture changing from Copper {112}<111> to {111}<112> with the increase in the rolling passes, and the equiaxed grains with a size of ～200 nm were formed, and the larger Mg2Si phases precipitated in the alloy.The strength and the accumulative strain of the accumulatively-rolled 6060 aluminum alloy increase, while the ductility and conductivity decrease with increasing the rolling passes.