Correlating the supercooled liquid region width with the fragility parameter in bulk metallic glasses

A linear correlation of fragility parameter D* with supercooled liquid region width Delta T-x for Ca-based bulk metallic glasses (BMGs) was revealed. This relationship is found in La- and Zr-based BMGs as well and extended to several glass-forming systems. The origin of this phenomenon lies in the close relation between crystallization and temperature dependence of viscosity. This relationship can be formulated by Delta T-x(0.33) = 6.8 x 10(-3) x (D*)(T-g(0.33)) + 2(K), indicating that the unique variation of the viscosity with the temperature correlates with the location and width of the supercooled liquid region. Moreover, an approximation of fragility parameter D* for BMGs can be evaluated by the formula. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3675910]