Combined grain refining and modification of conventional and rheo-cast A356 Al-Si alloy

This paper describes a comprehensive study on the combined addition of Ti-B grain refiner and Sr modifier elements to A356 Al-Si alloy. Using different qualitative and quantitative techniques in conventional and semi-solid metal castings, it is shown that, while the refiner and modifier elements affect respectively the nucleation and eutectic reactions, the combined addition not only replicates both individual element effects but also gives the added bonus of better globularity in the semi-solid metal process. A new innovative concept is introduced for fluidity measurement by using the magnitude of remaining liquid in the form of drainage, which is increased by combined treatment. (c) 2006 Elsevier Inc. All rights reserved.