Viscous flow behavior and thermal properties of bulk amorphous Pd₄₀Ni₁₀Cu₃₀P₂₀ alloys

Using differential scanning calorimetry, we observed one exothermic peak and a distinct melting endothermic peak from the as-quenched sample in an argon atmosphere. The activation energy and enthalpy for crystallization were found to be 193.0 kJ/mol, and 43.0 J/g, respectively. A supercooled liquid region extending over approximately 85 K. at a heating rate of 10 K/min is observed. Below T_x., the average specific heat difference between the liquid and solid phases increases with increasing annealing temperature indicating good glass-forming ability. Thermomechanical analysis (TMA) experiments showed that below the steady-state viscous-flow temperature the effective viscosity of all samples decreased with increasing temperature, with the highest applied compressive stress giving the greatest value of effective viscosity. By examining the relationships between the observed relative displacement, the applied stress and temperature, we found that an optimum temperature range for secondary working is about 620-629 K in this sample.