Microstructural feature of As-cast A-356 alloy modifiers with the addition of SrO

Abstract

To explore the effect of strontium on the structure of as-cast A356 alloy, the strontium was incorporated to the alloy by metallothermic reduction of SrO where the mineral was added to the melt through the submerged powders injection technique. The evaluation of the modification of the eutectic silicon and the chemical analysis of samples were done using optical microscopy (OP) and inductively coupled plasma (ICP), respectively, while microstructural analyses by scanning electron microscopy (SEM), and the injection time was variable. Magnesium was added to the melt to increase the reactivity and reduce the surface tension of the molten aluminum. It was possible to increase the strontium content from 0 to 0.027% after 20 minutes treatment. This concentration was sufficient to bring about full modification structure of eutectic silicon of as cast alloy A 356 and the acceptable quality metallurgical of alloy.