VISCOELASTIC BEHAVIOR IN INDIUM-TIN ALLOYS OVER A WIDE-RANGE OF FREQUENCIES AND TIMES

Experimental studies of dynamic and transient viscoelastic response we re conducted at 24 degrees C on gamma-(In-Sn) alloy, and high-frequenc y studies were conducted to extend the frequency range for eutectic In -Sn. The experiments were conducted in torsion using an instrument cap able of determining viscoelastic properties over more than ten decades of time and frequency. The damping, tan delta, followed a nu(-n) depe ndence, with n approximate to 0.2, over many decades of frequency nu. This dependence corresponds to a stretched-exponential relaxation func tion and is attributed to a dislocation point-defect mechanism. It is not consistent with a self-organized criticality dislocation model whi ch predicts that tan delta proportional to nu(-2).