Influences of Fe, Si and homogenization on electrical conductivity and mechanical properties of dilute Al–Mg–Si alloy

• Utilization of Fe in Al–Mg–Si alloys for higher electrical conductivity is proposed.
• Mechanical properties of the Al–0.5Mg–0.35Si–0.2Fe alloy was compensated by extra Si.
• Electrical conductivity of the above alloys can be further improved by homogenization.
• Tensile strength of the Al–Mg–Si–Fe alloy is also enhanced by homogenization.
• The underlying micro-mechanisms for the improvements of properties have been proposed.

The aluminium alloys with increased electrical conductivity and high strength are highly desirable for the application in electrical conductor industries. The dilute Al–Mg–Si alloy is considered as one candidate to reach a good combination of electrical conductivity and strength in Al alloys. While, the underlying effects of impurity elements such as Fe and some process treatment on the electrical properties of the alloy had not been well illustrated. Thus in the first part of this work, the influence of Fe element on electrical conductivity and mechanical properties of Al–Mg–Si alloy is investigated. A series of methods are put forward to reduce the harmful effect of Fe or to utilize this element. It is found that when a certain content of Fe is added into the Al–0.5Mg–0.35Si alloy, the electrical conductivity of the alloy can be improved. In contrast, the Brinell hardness and the ultimate tensile strength of the alloy are decreased. Whereas, the strengthening of the alloy can be offset by adding extra Si contents. In addition, the electrical conductivity and mechanical properties of the Al–0.5Mg–0.4Si–0.2Fe alloy can be further improved through homogenization treatment and the corresponding mechanism is also discussed. This work is proposed to help to improve the design and development of better materials for real applications in electrical conductor industries.