The Al-rich region of the Al-Fe-Mn alloy system

Phase equilibria in the Al-rich region of the Al-Fe-Mn alloy system were studied at 1070, 1020, 950, 875, 800, 740, 695 and 650 °C. The continuous region of the bcc solid solution was estimated between the Al-Mn and Al-Fe terminals. Also the isostructural high-temperature Al-Mn and Al-Fe γ1-phases (γ-brass type structure) form continuous regions. The Al6Mn, high-temperature T-Al11Mn4 and low-temperature γ2 phases dissolve up to 9.0, 14.5 and 31.0 at.% Fe, respectively, while the M-Al13Fe4, Al5Fe2 and Al2Fe phases dissolve up to 15.5, 11.5 and 10.0 at.% Mn, respectively. The thermodynamically stable decagonal D3-phase with periodicity of 1.25 nm in the specific direction and two periodic intermetallics designated φ (P63/mmc; a = 0.7554, c = 0.7872 nm) and κ (P63/m; a = 1.7630, c = 1.2506 nm) were identified. An additional ternary phase of unknown structure was also revealed.