Thermal Analysis of Grain Refinement and Modification of an A356 Cast Alloy.

Abstract

It is well known that grain refining and eutectic Si modification treatments provide benefits to aluminum alloys. The addition of master alloys makes it possible to obtain a fine grain size and a modified eutectic microstructure. The present research evaluates the combined effect of both treatments in an A356 alloy by thermic analysis of the cooling curves and micro- and macrostructural studies of the samples. Reviewing the thermal parameters of the cooling curves indicated that using 0.2%Ti and 0.03% Sr, a good level of eutectic phase modification, as well as a fine grain structure, is reached. The joint effect of both elements is involved in the alteration of the growth kinetics both of the primary phase and the eutectic phase.

Keywords: grain refining, eutectic Si modification, A356 alloy, solidification, thermal parameters, thermic analysis, microstructure, macrostructure.