Study of Al-Si alloys grain refinement by inoculation

Abstract

Abstract The grain size and morphology of any cast metal have significant influence on its mechanical properties. The subsequent processing required to achieve the desired mechanical properties can be presumed based on the grain microstructure morphology. Solidified grains of Aluminium Silicon (Al-Si) alloy contain columnar structures along the periphery, more predominantly in the cases of direct chill casting. These columnar shaped grains in mold casting propagate from the periphery to the center of the ingot. The fine equiaxed grains attributes to better strength for any metal and hence fine grain sizes are preferred to coarse columnar grains. Though there are various techniques available to achieve the columnar to equiaxed transition, this paper intends to provide an overview of refining the Al- Si alloy grain structures at the expense of master alloys inoculated with refiner chemical elements and a lateral emphasis is also given to the elements that perform as grain modifiers which modify the irregular hard primary Silicon and eutectic Silicon flakes prevailing in Al-Si alloys.