Optimizing microstructures of dilute Al–Fe–Si alloys designed with enhanced electrical conductivity and tensile strength

Abstract

Al alloys are playing more and more important roles in overhead power transmission and other electrical conductor applications, which makes high tensile strength and increased electrical conductivity of the alloy highly desirable. Due to the limitation of raw materials and production conditions, electrical conductivity of Al is generally in a low level because of adulteration of impurities such as Si. Thus, the control of the content and morphology of Si is a key factor to produce high quality Al conductors. In this work, the utilization of Fe to control the harmful effect of Si has been proposed by us. The influences of Fe content and subsequent homogenization treatment on dilute Al–Si alloy have been investigated. It reveals that the electrical conductivity of dilute Al–Si alloy can be improved with a certain addition of Fe. What's more, the ultimate tensile strength and electrical conductivity of Al–Fe–Si alloy can be further improved after homogenization. It is assumed that the good performances of the Al–Fe–Si alloy can be attributed to the formation and evolution of α-Al8Fe2Si ternary eutectic phase. In addition, it is also found that the evolution of α-phase can be promoted by enhanced homogenization temperature and grain refinement.