Glass to icosahedral phase transformation in Zr-based glassy metals

Electrical properties of icosahedral phases (I-phase) that precipitated in Zr₆₅Al_7.5Cu_7.5Ni₁₀M₁₀ (M=Ag, Pd), Zr₆₅Al_7.5Cu_12.5 Ni₁₀M₅ (M=Ag, Pd), Zr₆₅Pd₂₅Ni₁₀ and Zr₇₀Pd₂₀Ni₁₀ metallic glasses have been investigated. In-situ resistivity change with increasing temperature was measured at a heating rate of 0.67 K/s from room temperature. I-phase transformation was occurred in the supercooled liquid phase for Zr-Al-Cu-Ni-M glasses, followed by the crystallization to stable Zr₂Ni- and Zr₂Cu-type crystals. Ternary glasses exhibited the I-phase crystallization from the glass solid phase and subsequently the transformation of I-phase to crystal phases like Zr₂Ni and Zr₂Pd. The resistivity of I-phase decreased together with advancing I-phase precipitation, about 2 % compared to the resistivity of the supercooled liquid phase, for typical Zr₆₅Al_7.5Cu_7.5Ni₁₀Ag₁₀ glass. On the other hand, Zr₇₀Pd₂₀Ni₁₀ glass showed the resistivity increment of about 5 % just after completing I-phase crystallization. Low temperature conductivity of Zr₆₅Al_7.5Cu_7.5Ni₁₀Ag₁₀ and Zr₇₀ Pd₂₀Ni₁₀ glasses and I-phases may be explained by the weak localization model of conduction electron in the range from about 20 K to room temperature.