COST 507 - Repositório Aberto da Universidade do Porto

phase to be 11.2 and 11 wt% respectively. These measurements were however
conducted on samples where the cubic alpha-AlMnFeSi phase was also present which
means that the hexagonal phase would have to contain an unnaturally high amount of
Si compared to what is standard for the pure Al-Fe-Si system (without Mn). Corby
[77Cor] found that the hexagonal phase contained 8.7 wt% Si. A complete review of
the ternary phases included in the assessment is given in Table 1.
The calculated enthalpy of formation at 298.15K for the alpha and beta phase is 23.4
and 18.2 kJ/mol, while the experimental values determined by Moquet [71Moq] are
23.23 and 20.04 kJ/mol respectively.
The calculated diagrams generally reproduce the available experimental data well.
However, emphasis has been placed on achieving a good fit in the aluminium rich
corner, since this is where the bulk of the reliable data and the industrial interest is
focused. It must be pointed out that even here there are still important points which
have not been satisfactorily investigated such as the phase boundaries for Al 13 Fe 4 and
the alpha-AlFeSi phase at higher Si contents, and the solubility range for the delta-
AlFeSi phase. A redetermination of the invariant points and the enthalpy of formation
of at least one of the ternary phases would also improve the assessment. A comparison
between the calculated and experimental positions of the invariant points is shown in
Table 2.
As for the central part of the system, there is very little interest and thereby also little
data in this region of the phase diagram. Two ternary compounds τ_1 and τ_3 are
included in the diagram but their compositions and appearance in the diagram is
uncertain. Later work has revealed the probable existence of several other phases
[81 Zar], but they can not be included in the diagram before more information, such as
melting points, enthalpies and equilibria with other phases have been investigated.
4 References
[40Tak] H. P. Takeda and K. Mutuzaki, Tetso to Hagane, 1940, 26, 335.
[50Phr G. Phragmen, J. Inst. Met., 1950, 77, 489.
[51Pra] J. N. Pratt and G. V. Raynor, J. Inst. Metals, 1951, 79, 211.
[54Arm] M. Armand, Congres International de l'Aluminium, 1954.
[55BIa] P. J. Black, Philos. Mag., 1955, 46, 401.
[59Phi]
H. W. L. Phillips, Annotated Equilibrium Diagrams of some Aluminium
Alloy Systems, Inst. Met., London, 1959.
[67Mun] D. Munson, J. Inst. Met., 1967, 95, 217.
[71Moq]
J. L. Moq, Contribution a l'estimasjon des grandeurs thermodynamiques
des composes intermetalliques et des entropies de fusion des eutectiques
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