Viscous flow behavior and thermal properties of bulk amorphous Pd40Ni10CU30P20 alloys

Using differential scanning calorimetry, we observed one exothermic peak an d a distinct melting endothermic peak from the as-quenched sample in an arg on 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 o bserved. Below T-x, the average specific heat difference between the liquid and solid phases increases with increasing annealing temperature indicatin g good glass-forming ability. Thermomechanical analysis (TMA) experiments s howed that below the steady-state viscous-flow temperature the effective vi scosity of all samples decreased with increasing temperature, with the high est applied compressive stress giving the greatest value of effective visco sity. By examining the relationships between the observed relative displace ment, the applied stress and temperature, we found that an optimum temperat ure range for secondary working is about 620-629 K in this sample. (C) 2001 Elsevier Science B.V. All rights reserved.