New criterion of glass forming ability for bulk metallic glasses

It has been confirmed that glass-forming ability (GFA) is related to not only liquid phase stability but also the crystallization resistance. In this study, it was found the liquidus temperature T-l and supercooled liquid region T-x-T-g could reflect the stability of glass-forming liquids at the equilibrium and undercooled state, respectively, while the onset crystallization temperature T-x could indicate the crystallization resistance during glass formation. Thus, a modified gamma parameter, defined as gamma(m)=(2T(x)-T-g)/T-l, has been established. This parameter shows an excellent correlation with the GFA of bulk metallic glasses, with the statistical correlation factor of R-2=0.931. (c) 2007 American Institute of Physics.