Grain refinement (GR) plays an important role in cast and wrought Al alloys. GR has several advantages when casting, benefits being related to fine scale distribution of second phases and of microporosity, amelioration of castability with reduction of shrinkage porosity, better mechanical properties and higher strength, as well as fatigue life.
The proposed paper aims to present a full review of commercially available GR for Al alloys castings, taking into consideration the final grain size in the product and the melting and casting practice used, type of treated alloys.
Series of experimental results obtained into the casting laboratories at Politecnico di Torino and aimed to verify the effects of different GR on certain traditional and innovative alloys will be presented and discussed. The appropriate use of GR always contributes to improved mechanical properties, particularly strength and ductility, and to refined porosity which leads to an additional improvement in mechanical properties.