Nanocrystalline Icosahedral phase formation in melt spun Ti-Zr-Ni alloys

Abstract

The paper reports Icosahedral phase (i-phase) formation in the nanocrystalline state in Ti55Zr20Ni25 and Zr55Ti25Ni20 alloys. While nanocrystalline i-phase forms directly from the melt during melt spinning at low wheel velocity of 20 m/s, nanoquasicrystallization of amorphous phase has been observed on subsequent annealing after melt spinning at higher wheel velocities of 30 and 40 m/s. The i-phase is stable up to 873 K in Ti-rich alloy, while it transforms to crystalline phases in Zr-rich alloy below this temperature. The i-phase formed both directly from the melt and from the amorphous phase is much finer in Zr-rich alloy compared to Ti-rich alloy.