CALCULATION OF SOME METALLIC-GLASS PROPERTIES, BASED ON THE USE OF A GAUSSIAN DISTRIBUTION FOR THE NEAREST-NEIGHBOR DISTANCE .2. DIFFUSION AND VISCOSITY PROPERTIES

Starting from experimental data in the literature, a strong, nearly linear correlation is demonstrated between the apparent activation energy for diffusion and the logarithm of the pre-exponential factor. This correlation, as well as the extreme values found for the pre-exponential factor, are explained on the basis of an activation energy spectrum. The latter is assumed to be Gaussian, which seems reasonable, bearing in mind that the activation energy depends on the interatomic distances, and that the nearest-neighbour distances nearly follow a Gaussian distribution. Further, the viscosity of amorphous material is studied, using again a distribution of energy barriers. Within this description, an explanation is given for the experimentally observed linear increase in viscosity with time of an as-quenched amorphous alloy during isothermal measurements.