Synthesis and devitrification of glassy Zr-Ti-Ni and Zr-Hf-Ni ternary alloys

Two alloys of nominal compositions Zr41.5Ti41.5Ni17 and Zr41.5Hf41.5Ni17 have been melt spun at 40 ms(-1) wheel speed. Under this processing condition Zr-Ti-Ni alloy becomes amorphous and the Zr-Hf-Ni alloy precipitates a cubic phase with 4.95 Angstrom lattice parameter in the amorphous matrix. The Zr-Ti-Ni alloy, upon annealing, precipitates a nanoquasicrystalline phase, which at the later stages of crystallisation transforms into cF96 NiZr2 phase. The amorphous phase in Zr-Hf-Ni alloy upon annealing precipitates the same cubic phase with 4.95 Angstrom lattice parameter. The lower glass forming ability of Zr-Hf-Ni compared to Zr-Ti-Ni and nanoquasicrystallisation in Zr-Ti-Ni alloy can be explained by taking into consideration the atomic size differences among Ti, Zr and Hf. (C) 2004 Elsevier B.V. All rights reserved.