Precipitation of Nano-Scale Icosahedral Quasicrystalline Phase in Amorphous Hf₇₃Pd₂₇ Alloy

抄録

An amorphous Hf₇₃Pd₂₇ binary alloy was prepared by a single roller melt-spinning method. The crystallization process was studied using differential scanning calorimetry, X-ray diffraction and transmission electron microscope. The crystallization proceeds through two exothermic reactions, in which the low temperature one corresponds to the precipitation of an icosahedral quasicrystalline phase (I-phase). Further annealing causes the phase transformation from the I-phase to the Hf₂Pd crystal, indicating the metastable character of the I-phase. The present results imply that the precipitation of an I-phase in the Hf–Pd binary alloy is the basis for its formation in the Hf–Al–Ni–Cu–Pd and Hf–Al–Ni–Pd alloys reported previously.