Recovery of less relaxed state in Zr-Al-Ni- Cu bulk metallic glass annealed above glass transition temperature

The relaxation state of metallic glass is determined by the cooling rate at low temperatures in a supercooled liquid. Based on this result, we can control the relaxation state of Zr55Al10Ni5Cu30 bulk metallic glass by recovery annealing just above the glass transition temperature (T-g). We rejuvenate the relaxation state for approximately 50% in the enthalpy of relaxation at a cooling rate of 4.4K/s after annealing, as compared with that of the as-cast state. Mechanical softening also occurred upon the rejuvenation. The results suggest another method of controlling the structure of metallic glasses to improve their properties. (C) 2013 AIP Publishing LLC.