Viscoelastic behaviour in indium-tin alloys over a wide range of frequencies and times

Experimental studies of dynamic and transient viscoelastic response were conducted at 24°C on γ-(In-Sn) alloy, and high-frequency studies were conducted to extend the frequency range for eutectic In-Sn. The experiments were conducted in torsion using an instrument capable of determining viscoelastic properties over more than ten decades of time and frequency. The damping, tan δ, followed a υ-n dependence, with n≈0·2, over many decades of frequency υ. This dependence corresponds to a stretched-exponential relaxation function and is attributed to a dislocation point-defect mechanism. It is not consistent with a self-organized criticality dislocation model which predicts that tan δ ∝ υ-2.