Microstructural improvement of semi solid hypoeutectic Al-Si foundry alloys through boron addition

Abstract

Comprehensive study was performed on the impact of grain refiners addition to the microstructural evolution of semi-solid hypoeutectic Al-Si slurries. The most widely used industrial refiners are AlTiB master alloys in spite of their well proven drawbacks including fading and settling of the so-called nucleant particles. A1-B master alloy is re-introduced as a potent substitute of traditional AlTiB master alloys. In semi solid casting of Al7Si0.35Mg alloy, it is shown that by boron addition, the number of primary Al-globules is increased. Improved globuiarity coupled with smaller primary particle size leads to superior rheological characteristics of the SSM billets.