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

Abstract

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 of the 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)₂Ni solid solution phase by a solid state reaction.