Formation of Metastable Aluminides in Alloys of Al – Hf – Sc (Ti) Systems

The methods of optical and scanning electron microscopy and x-ray spectrum microanalysis are used to study and to compare the special features of formation of metastable trialuminides under rapid crystallization of superheated melts of the Al – Hf – Sc and Al – Hf – Ti systems. Heating of such melts by over 100°C above the liquidus temperature yields Al n (Hf 1– x S c x ) and Al n (Hf 1– x Ti x ) aluminides with a cubic lattice of structural type L1 2 .