Amorphous (Ti,Zr, Hf)NiCu ternary alloys with a wide supercooled liquid region

Ternary TiNiCu, ZrNiCu and HfNiCu amorphous alloys were found to exhibit a distinct glass transition combined with rather wide supercooled liquid region before crystallization. The largest temperature interval of the supercooled liquid region defined by the difference between T_g T_x, i.e. ΔT_x (= T_x-T_g, is 55 K for Ti₅₀Ni₂₅Cu₂₅, 60 K for Zr₆₀Ni₂₀Cu₂₀ and 65 K for Hf₆₀Ni₂₀Cu₂₀. These amorphous alloys with the largest ΔT_x values also exhibit the highest T_x and the lowest melting temperature and crystallize through asingle-stage exothermic reaction leading to the simultaneous precipitation of more than two kinds of compound. It is therefore presumed that the appearance of the wide supercooled liquid region before crsystallization is due mainly to the necessary of the redistribution of the constituent elements for the precipitation of the compounds from the homogeneously mixed amorphous structure.