The effect of Magnesium on the modifying efficiency of strontium in A356 alloy

Abstract

This study was undertaken to investigate the effect of different concentrations of magnesium (0.2%, 0.3%, and 0.4%) on the modifying efficiency of Sr in aluminium alloy A356. Both sand casting and gravity die castings were taken for the same composition. Modifying efficiency was studied quantitatively by measuring the size and shape of Si eutectic particles by using ImageJ image analyser and giving a Modification Rating (MR), developed by American Foundrymen’s Society (AFS), for each microstructure ranging from 1 to 6, 1 being unmodified and 6 being completely modified very fine structures. Characterisation was done with optical microscope and SEM equipped with EDS and XRD. Mechanical testing involved hardness test in both as cast and standard T6 condition.