DC Casting, Deformation and Strengthening of Al-Si Alloys

Abstract

Al-Si alloys are widely used as cast alloys for their excellent castability, low thermal expansion coefficient, good wear resistance and corrosion resistance properties. However, the poor ductility of these alloys, caused by the presence of coarse and non-deformable Si phase in the as-cast state, has inhibited their applications as wrought materials. Recently, a process based on traditional technologies, i.e., direct chill (DC) casting followed by hot deformation and heat treatment, has been developed for potential mass production of wrought Al-Si alloys with superior mechanical properties in view of their strength and ductility. In this work, the microstructural evolutions of DC cast Al-Si alloys involved in solidification, recrystallization and precipitation during the processing are highlighted, aiming at understanding the correlations between the microstructures and the mechanical properties.