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Using low-stress pseudoshear deformation, we measured the ambient-temperaturecreep-recovery behavior of polycrystalline indium. The &+J diagram shows three regions with increasing stress: stress exponents of 1.05, 7.4, and 2.0. The diagram resembles remarkably the dislocation-velocity-shear-stressdiagrams reported for various materials by many authors, who interpreted the diagrams by dislocation dynamics. Applying an extended Burgers model (two Kelvin-Voigt elements) gave for the three regions the following relaxation times z2 and .c3 (in seconds):(1) 11, 123; (2) 10, 132; (3) 12, 154. Thus, z, is nearly stress independent, and .c2 increases with increasing stress. Laplaceantransformation of our ~( t )measurements to get the retardation-time distribution function g(In z) indicates in all three regions a strong peak near .c2 = 3 s and a weaker, broader peak near 23 = 150 s. These agree surprisingly well with the Burgers dashpot-spring-model results. We analyzed the recovery part of the strain ~( t ) to obtain e-lcf) curves.

Internal friction of (Si02)l-x (GeO2h glasses (x = 0, 5, 10, 24 and 100 mole%) is measured at temperatures between 1.6 and 280 K. The data are fitted with the equations for thermally activated relaxation with distribuling activation energies in symmetrical double-well potentials. From the determined relaxation strength spectra for each sample, the contributions from each type of microscopic structural units are calculated assuming that transverse motion of the bridging 0 atom in Si-0-Si, Si-0-Ge or Ge-0-Ge bridge model) is the microscopic unit responsible for relaxation. For instance, the magnitude of internal friction for Si02-5% Ge02 or 24% GeO2 is calculated from the data of pure SiO2, Si02-10% GeO2 and pure GeO2. The calculated results agree well with the measurements of Si02-5% GeO2 and Si02-24% GeO2. Thus T model is shown to be quantitatively consistent with internal friction of S i O~G e 0 2 binary glasses.

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