2006 Volume 47 Issue 8 Pages 1926-1929
Wide Zr55Al10Ni5Cu30 metallic glassy alloy sheets were successfully produced by a twin-roller casting method. The glassy alloy sheet of 12 mm in width, 0.19 mm in thickness and 650 mm in length has flat surfaces with highly white luster. The exothermic heat of the sample keeps almost constant up to 108 ks at 663 K, decreases gradually with increasing time and becomes almost zero at 1210 ks, in agreement with distinct precipitation of crystallites identified as CuZr2 and Al5Ni3Zr2.
Mechanical properties, which are tensile stress, fracture strain and hardness, were measured for the samples annealed at various temperatures for different times. At high annealing temperatures slightly above and below Tg, the glassy alloy suffers embrittlement by the beginning of crystallization. The glassy alloys annealed at the temperatures much lower than Tg and Tx become brittle after prolonged annealing, in spite of the fact that they show the glassy structure by XRD and DSC.