Phase selection in Al-TM-RE alloys: nanocrystalline Al versus intermetallics

Al-TM-RE (TM: transition metal, RE: rare earth metal) and Al-RE alloys were analysed with the aim of studying phase selection under various processing conditions. The metastable phases formed in binary Al-rich systems (notabl y Al-Sm) are revised for a unified interpretation of the literature. Tire g roups of alloys had different behaviour as for phase selection, In Al88Fe9N d3 and Al87Ni10Ce3 stable intermetallic compounds form as primary; phases d uring solidification. Nanocrystalline Al is formed at high undercooling. Th is may occur directly in rapid solidification or when fully amorphous mater ials ar c suitably annealed. Iii Al90Sm8Ni2 and Al90Sm8Fe2 metastable inter metallics form during rapid solidification together with a fraction of amor phous phase. whereas nanocrystalline Ai forms on annealing the amorphous ph ase. (C) 2001 Elsevier Science B.V. All rights reserved.