Heterogeneous nucleation of solidification of equilibrium and metastable phases in melt-spun Al-Fe-Si alloys

1xxx series Al-0.3 wt% Fe-0.1 wt% Si alloys with different impurity contents have been melt spun to produce microstructures of fine scale similar to 0.1-0.2 mu m diameter secondary phase particles entrained in a higher melting point Al matrix. The melting and resolidification behaviour of the secondary phase particles while entrained in the solid matrix was monitored using differential scanning calorimetry, to simulate the nucleation of secondary phases in liquid interdendritic regions during the final stages of solidification in casting. The effect of impurities on the nucleation of solidification behaviour, and in particular on secondary phase selection, has been investigated by comparison of commercial and higher purity alloys. (C) 1997 Elsevier Science S.A.