High temperature backgrounds
January 30th, 2010 by admin
This plot shows viscoelastic behavior of an indium-tin alloy over more than eleven decades of time and frequency, at 23 degrees C, with no appeal to time-temperature superposition. It is not consistent with a self-organized criticality dislocation model which predicts n = -2, Dislocation damping in metals is relevant to development of high damping metals, the behaviour of solders and of support wires in Cavendish balances. This frequency dependence of internal friction corresponds to a stretched exponential visco elastic foam mattresses relaxation function, and is attributed to a dislocation-point defect mechanism. The high temperature background is observed in these alloys at room temperature. Viscoelastic damping tan delta approximately follows a power law dependence over about four decades of frequency.