STABLE AND METASTABLE PHASE EQUILIBRIA IN THE Al-Mn SYSTEM.

The aim of the investigation was resolution of certain features of the phase diagram. The experimental approach was guided by assessment of the literature and modeling of the thermodynamics of the system. Two phases of approximate stoichiometry 'Al//4Mn' ( lambda and mu ) are present in stable equilibrium. The liquids and stable equilibrium invariant reactions as proposed by T. Goedecke and W. Koester have been verified. A map has been made of the successive nonequilibrium phase transformations of as-splat quenched alloys. The thermodynamic calculation allows interpretation of reaction sequences during cooling in terms of the metastable invariant reactions involving (Al), Al//6Mn, lambda , mu , phi , and Al//1//1Mn//4 phases.