Glassy and icosahedral phases in rapidly solidified Ti–Zr–Hf–(Fe, Co or Ni) alloys

The icosahedral quasicrystalline, amorphous plus crystalline and glassy phases were formed in $Ti₄₀Zr₂₀Hf₂₀(3d-LTM)₂₀$ alloys (3d-LTM = 3d late transition metals Fe, Co and Ni). The icosahedral phase formed in the melt-spun $Ti₄₀Zr₂₀Hf₂₀Fe₂₀$ 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 $Hf₂Fe$ 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 $Ti₄₀Zr₂₀Hf₂₀Co₂₀$ 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 $Ti₄₀Zr₂₀Hf₂₀Ni₂₀$ alloy transformed to a big-cubic fcc $(Zr,Ti)₂$ Ni solid solution phase by a solid state reaction.