Intermetallic phases and phase reactions in Zn-Mg (<40Â at.%)-Y (<20Â at.%) region

Single phase regions of the icosahedral quasicrystal and the hexagonal (Zn, Mg)58Y13, (Zn, Mg)5Y, and Z (a ternary phase containing 6-8 at.% Y) in the Zn-Mg (0-40 at.%)-Y (0-25 at.%) region have been determined. A tentative isothermal section at 600 °C was proposed. The (Zn, Mg)5Y and the icosahedral phase have wide ranges of Mg content and are the dominant phases in these alloys. The hexagonal (Zn, Mg)5Y is resulted from the substitution of Mg for Zn in the binary Zn5Y and therefore they are isostructural, so are also the hexagonal Zn58Y13 and (Zn, Mg)58Y13 phases. Reactions among the intermetallic phases in this composition range during cooling were studied. Similar phase reactions have also been observed in the Zn-Mg-Ho/Er alloys.