VISCOUS-FLOW BEHAVIOR AND THERMAL-STABILITY OF NI100-XPX METALLIC GLASSES FROM NI84P16 TO NI79P21

The viscous flow behaviour and crystallization features of seven melt spun Ni100-xPx (16<x<21 at%) amorphous alloys have been studied in order to determine the inter-relation between these two processes. The experimental results obtained showed well-defined concentration dependences of the onset temperature T(on), the temperature of the maximal rate of heat release T(max), the enthalpy DELTAH(x) and of the activation energy Q(x) of the crystallization process. A systematic shift of the viscosity-temperature dependences to higher viscosity values with increasing P-content is observed. The viscosity values eta(T(g)) at the glass transition temperatures, T(g), are very near to the theoretically expected value of 10(12) Pa s. The activation energies Q(eta) of viscous flow at temperatures higher and lower than T(g) were also calculated. A good agreement between Q(x) and Q(eta) (T>T(g)) of the alloys with T(g)<T(on) was established. The crystallization processes in Ni100-xPx amorphous systems are governed by viscous flow.