Mössbauer spectroscopy was used for the study of AlFeSi intermetallic compounds formed in direct chill cast (DC) aluminium billets in as cast state and after subsequent heat treatments performed between 450 and 620°C. The Mössbauer parameters of ternary compounds conceivable under such conditions, i.e. cubic and hexagonal α-(AlFeSi), β-(AlFeSi) and γ-(AlFeSi), were determined by the measurement of samples prepared directly for that purpose. Besides ternary phases Al6Fe, Al3Fe and Al(Fe) solid solution were also searched for in the DC billets. It was found that both the intial phase composition of the billets and the phase transformations which took place during heat treatments depended on the iron to silicon ratio of the alloy. In the Al-0.54 m% Fe-0.95 m% Si alloy, namely, only β-(AlFeSi) was found up to 575°C, while the initial Al6Fe + cubic α-(AlFeSi) composition of the Al-0.58m% Fe-0.21 m% Si alloy changed gradually to A13 Fe + hexagonal α-(AlFeSi).
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