Reinvestigation of the Al-Mn-Pd alloy system in the vicinity of the T- and R-phases

The liquidus and solidus surfaces of the Al-Mn-Pd alloy system as well as partial isothermal sections at 950, 900, 850, 800, 750, 680 and 650 °C in the vicinity of the T- and R-phases were determined. Non-variant reactions involving T, R and neighbouring phases are interpreted. The relationship between the chemical inhomogeneity of the as-solidified T-phase and the geometry of its solidus surface is discussed. The dependence of the T-phase lattice parameters on the Pd content was determined. The thermodynamic stability of the ternary R-phase, which is structurally closely related to T, is clarified.