Numerical Modelling and Experimental Study of Solidification Behaviour of Al-mg2si Composite Sheet Fabricated Using Continuous Casting Route

Abstract

Owing to manufacturing challenges, the fabrication of thin sheets of metal matrix composites has been an area of concern for sheet manufacturers. Converting a billet of composite into a sheet using rolling and extrusion is quite energy-intensive and prone to cracking using the conventional casting route. To address this issue, the present study explores the development of particle-reinforced near eutectic Al-Mg2Si composite sheets using a vertical twin-roll continuous casting process. The numerical simulation involves fluid flow, solidification, and heat transfer analysis of the twin-roll continuous casting process for producing thin strips. Processing parameters such as the velocity of rolls and superheat temperature of the melt are optimized to successfully convert the melt into a sheet of composite material. A combined numerical and experimental study shows that the CC process is more sensitive to the casting speed. A small change in roller speed (2 rpm) significantly affects the solidified fraction at the roller exit. Optimizing the casting speed to 0.072 m/s and inlet temperature to 886 K, an in-situ Al-Mg2Si composite sheet of 3 mm thickness is successfully cast. The particle distribution along the casting direction of the sheet is uniform, ensuring the homogeneous mechanical properties reported in terms of hardness. The entire process does not require external stirring to get uniform distribution of the reinforced particles.