Phase Diagrams of Al–Si System

Abstract

Thermo-Calc software was used to deduce the phase diagram of the Al–Si binary system, which is a necessary step to understand the more complicated systems containing Si–Al binary. The phase diagram contains two solid solution phases (α-Al) (FCC_Al) and diamond cubic Si (Diamond-A4), a liquid phase, and three mixed phases; FCC_Al+Diamond-A4, liquid+FCC_Al, and liquid+Diamond A4. The melting points of Al and Si are 932.77 and 1687.73K (659.62 and 1414.58°C), respectively. From the phase diagram, the eutectic reaction occurs at 12.49 mass percent Si and 850.22K (577.07°C). The maximum solubility of Si in Al occurs at the eutectic temperature and 1.547 mass percent Si, and that of Al in Si occurs at 0.1576 Al mass percent at 950.22K (677.07°C).