SUPERCOOLED LIQUID REGION IN ZR-CU BASED BULK AMORPHOUS-ALLOYS

A comparative study of glass-forming ability and stability of the supe r-cooled liquid for Zr40Ti10Cu50 (A), Zr40Ti5Y5Cu50 (B), Zr65Al7.5Cu17 .5Ni10 (C) bulk amorphous alloys was carried out. The glass-forming ab ility, evaluated as the maximum thickness of the amorphous layer in a cone-shape ingot was found to be 2.8, 0.1, and 2.0-2.5 mm for the A-, B-, and C-alloy, respectively. The B- and C alloys have high stability of the supercooled liquid under both continuous heating and isotherma l annealing. The effect of an additional expansion of the supercooled liquid region as a result of short precrystallization was noted on rep eated heating of the C-alloy. The mechanisms which control glass-formi ng ability and stability of the supercooled liquid are discussed.