INTERNAL-FRICTION AND CREEP-RECOVERY IN INDIUM

Using low-stress pseudoshear deformation, we measured the ambient-temp erature creep-recovery behavior of polycrystalline indium. The epsilon -sigma diagram shows three regions with increasing stress: stress expo nents of 1.05, 7.4, and 2.0. The diagram resembles remarkably the disl ocation-velocity-shear-stress diagrams reported for various materials by many authors, who interpreted the diagrams by dislocation dynamics. Applying an extended Burgers model (two Kelvin-Voigt elements) gave f or the three regions the following relaxation times tau(2) and tau(3) (in seconds): (1) 11, 123; (2) 10, 132; (3) 12, 154. Thus, tau(1) is n early stress independent, and tau(2) increases with increasing stress. Laplacean transformation of our epsilon(t) measurements to get the re tardation-time distribution function g(In tau) indicates in all three regions a strong peak near tau(2)=3 s and a weaker, broader peak near tau(3)=150 s. These agree surprisingly well with the Burgers dashpot-s pring-model results. We analyzed the recovery part of the strain epsil on(t) to obtain Q(-1)(f) curves.