LOSS TANGENT DISTRIBUTION FUNCTION - APPLICATIONS TO METALS AND POLYMERS

The mechanical damping behaviour of both metals and polymers is analys ed within the theory of the tangent distribution function and its equi valent form, the integrated distribution, which have been recently int roduced in the literature. The procedure developed is applied to exper imental data on the Zener relaxation in Ag-24 at. % Zn, as a function of temperature, for different excitation frequencies. This relaxation process shows a behaviour of the Debye type, and the results obtained are compared with values reported previously. Finally, the method is a pplied to internal-friction peaks reported in amorphous polyvinyl chlo ride, for temperatures near the glass transition. A non-singular tange nt distribution function is observed in the transition process, togeth er with a temperature dependence of the activation enthalpy, which is discussed in terms of critical phenomena.