Neutron diffraction analysis of phase precipitation in solidification of hypereutectic Al-Si alloys with the addition of Cu and Mg

Abstract

A good understanding of the kinetics of evolution of solid phases during solidification of hypereutectic aluminum alloys is a key factor in controlling the as-cast microstructure and, in turn, enhancing the service properties of industrial alloys. A study was performed to evaluate the solidification kinetics for two hypereutectic Al-19%Si alloys with the addition of 3%Cu and 3%Cu+1%Mg. This study included thermodynamic calculations of the solidification process using the FactSage™ 6.2 software package, as well as experimental thermal analysis, and neutron diffraction. The study revealed kinetics of solid Al, solid Si, Al2Cu, and Mg2Si evolution, as well as an individual effect of Cu and Mg alloying additions on the solidification path of the Al-Si system.