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−xAl10 (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 5−39 m/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 85 μm. The width of supercooled liquid region, ΔTx and the reduced glass transition temperature, Trg 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.