The improvement of electrical conductivity of hypoeutectic Al-Si alloys achieved by composite melt treatment

Abstract

Hypoeutectic Al-Si alloys are one of common material for overhead transmission lines. However, electrical conductivity and mechanical property are hard to be improved simultaneously, which limits its application. Boron treatment and Sr modification can improve electrical conductivity and mechanical property by purify Al matrix and modify eutectic Si. According to our study, Ti assistant boron treatment (TBT) or Sr modification separately is good to improve electrical conductivity, but TBT with Sr modification at the same time is not effective to improve electrical conductivity. Thus Al-3B-5Sr was proposed to modify the microstructure of hypoeutectic Al-Si, improving the electrical conductivity and mechanical property at the same time. Based on this, a new composite melt treatment was proposed and high electrical conductivity with good mechanical property can be achieved simultaneously.