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 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.