Simplified Rheocasting of Al-Si Alloys Sheared by Mechanical Stirring
A rheocasting prototype for the semi-solid processing of Al-Si alloys was designed and assembled at laboratory scale, this is the first attempt for the development of S2P equipment in Mexico. This work describes the simplified method of mechanical stirring and the calculation of the theoretical parameters for the operation of the experimental device in order to provide shear rate into the slurry by a stainless steel impeller inside a crucible made of hot work steel. Moreover, a vertical pressure die-rheocasting system it is applied with the semi-solid alloy flowing counter the position of the injector during the displacement of the crucible in order to fill the mold. New design is applied in this rheocasting equipment.The semi-solid state with thixotropic behavior is produced in the stirred AlSi7Mg alloy; this condition allows the non-dendritic morphology because the intensively stirring at the beginning of the solidification produces the trimming of dendrites, growing so the primary solid (α) in globular shape surrounded by eutectic microstructure. Preliminary microstructural characterization was performed.