The Al-rich region of the Al-Mn-Ni alloy system. Part I: Ternary phases at 750-950 °C

▶ The Al-Mn-Ni alloy system was investigated by means of SEM, TEM, powder XRD and DTA in the Al-rich region ranging from 60 to 100 at.% Al in the temperature range from 750 to 950 °C. ▶ Two new ternary intermetallic compounds were revealed: the φ-phase (Al5Co2-type, hP26, P63/mmc: a = 0.76632(16) and c = 0.78296(15) nm) and the κ-phase (κ-Al14.4Cr3.4Nil.1-type, hP227, P63/m: a = 1.7625(10) and c = 1.2516(10) nm). The formation of the O-phase (Pmmn; oP650; O-Al77Cr14Pd9-type; a = 2.3316(16), b = 1.2424(15) and c = 3.2648(14) nm) was confirmed and its chemical composition as well as thermodynamic stability was specified. ▶ Close relationship between the hexagonal phases φ, κ and μ as well as the orthorhombic phases T, R and O has been discussed.