Thermal and Microstructural Analysis of an A356 Aluminium Alloy Solidified under the Effect of Magnetic Stirring

The solidification kinetics and microstructural characteristics of an A356 aluminum alloy subjected to magnetic stirring during solidification was studied by metallographic and thermal analyses. The alloy was heated to 680°C (1256°F) and poured into molds held at 200°C (392°F). Some samples were allowed to solidify in a conventional manner, whereas other samples solidified while under the influence of a permanent rotary magnetic field. The cooling curves were recorded to evaluate the effect that stirring exerts on solidification. Thermal analyses of these curves show that the temperatures associated with the solidification of aluminum dendrites and the Al-Si eutectic are reduced when a magnetic field is imposed. Metallographic observation of the samples revealed microstructural refining.