Glassy and icosahedral phases in rapidly solidified Ti-Zr-Hf-(Fe, Co orNi) alloys

Abstract

The icosahedral quasicrystalline, amorphous plus crystalline and glassy phases were formed in $Ti_{40}Zr_{20}Hf_{20}(3d-LTM)_{20}$ alloys (3d-LTM = 3d late transition metals Fe, Co and Ni). The icosahedral phase formed in the melt-spun $Ti_{40}Zr_{20}Hf_{20}Fe_{20}$ alloy is metastable and the average size ofthe quasicrystalline icosahedral particles precipitated in the amorphous matrix is 5 nm. The metastable icosahedral phase transformed to a big-cubic fcc $Hf_{2}Fe$ phase with the grain size of about 20 nm after annealing for 1.8 ks at 841 K. The glassy phase was formed in the melt-spun $Ti_{40}Zr_{20}Hf_{20}Co_{20}$ alloy and no metastable phase was found to form during the transformation from glassy phase to a stable crystalline phase. Icosaheadral phase formed in the melt-spun $Ti_{40}Zr_{20}Hf_{20}Ni_{20}$ alloy transformed to a big-cubic fcc $(Zr,Ti)_{2}$ Ni solid solution phase by a solid state reaction