Glass-forming ability of melt-spun multicomponent (Ti, Zr, Hf)-(Cu, Ni, Co)-Al alloys with equiatomic substitution

(Ti0.33Zr0.33Hf0.33)(x)(Ni0.33Cu0.33Co0.33)(90-x)Al-10 (x = 50, 55, 60) multicomponent alloys with equiatomic substitution for early and late transition metal contents were rapidly quenched by melt-spinning with the wheel speeds of 5-39m/s. Structural features of the as-quenched ribbons were characterized using X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. Using the wheel speeds higher than 30 m/s, fully glassy ribbons are obtained for all three alloys. With increasing content of the early transition metals, the glass-forming ability of the alloys was degraded. For the best glass-forming alloy at x = 50, the maximum thickness of fully glassy alloy ribbons reached about 85mum. The width of supercooled liquid region, DeltaT(x) and the reduced glass transition temperature, T-rg for this glassy alloy was determined to be 124 K and 0.47, respectively. Compared with the (Ti, Zr, Hf)-(Cu, Ni, Ag)-Al system, the glass-forming ability of the alloys was improved by the substitution of Co for Ag in the component of late transition metals group. (C) 2004 Elsevier B.V. All rights reserved.