Amorphous (Zr-Y)₆₀Al₁₅Ni₂₅ Alloys with Two Supercooled Liquid Regions

An amorphous phase exhibiting two distinguishable supercooled liquid regions was found in quaternary (Zr-Y)₆₀Al₁₅Ni₂₅ alloys in which the main constituent elements of Zr and Y are immiscible in a solid state. The first- and second-stage supercooled liquid regions are observed in the temperature ranges of 640 to 664 K and 763 to 810 K, respectively, accompanied by the two-distinguishable exothermic peaks due to crystallization after the appearance of the supercooled liquid regions. The temperatures of the first- and the second-reactions appear to correspond to those for ternary Y₆₀Al₁₅Ni₂₅and Zr₆₀Al₁₅Ni₂₅ amorphous alloys, respectively. The simultaneous dissolution of the immiscible Zr and Y elements is essential for the appearance of the two-stage supercooled liquid regions. From the appearance of the second-stage supercooled liquid region, it is concluded that the precipitation of the primary crystalline phase does not exert detrious influence on the appearance of the supercooled liquid region.