Vacuum hot pressing of gas-atomized Ni-Zr-Ti-Si-Sn amorphous powder

Abstract

Fully amorphous Ni57Zr20Ti18Si3Sn2 powders without any crystallinity are successfully fabricated in the particle size range below 75 mum by gas-atomization method. Gas-atomized Ni57Zr20Ti18Si3Sn2 amorphous powder exhibits the glass transition temperature (T-g) of 828 K and the crystallization temperature (T-x) of 886 K. The gas-atomized Ni57Zr20Ti18Si3Sn2 amorphous powder posesses a supercooled liquid region (DeltaTX) of 58 K. Based on the determined consolidation condition, the gas-atomized Ni57Zr20Ti18Si3Sn2 amorphous powder was consolidated by a vacuum hot pressing apparatus. The optimum consolidation conditions were determined by isothermal annealing of Ni57Zr20Ti18Si3Sn2 amorphous powder. The consolidated bulk Ni57Zr20Ti18Si3Sn2 samples show completely amorphous on processing after consolidation. The relative density and hardness of the consolidated bulk Ni57Zr20Ti18Si3Sn2 compacts are greater than 99 % and 800 Hv, respectively. (C) 2003 Elsevier B.V. All rights reserved.