Refinement of the grain size of the LM25 alloy (A356) by 96Al-2Nb-2B master alloy

Nb-based intermetallics contained in the master alloy act as potent heterogeneous nucleation substrate for the nucleation of primary Al dendrites. The addition of the 96Al-2Nb-2B master alloy to the LM25 alloy permits to significantly refine its microstructural features and the refinement is achieved in a great range of cooling rates. The formation of columnar grains at slow cooling rates is prevented.