Experimental studies were made of the dynamic and transient viscoelastic responses of the  phase at 24C. The experiments were carried out in torsion by using an instrument that was capable of determining viscoelastic properties over more than 10 decades of time and frequency. It was found that the damping obeyed a power-law dependence upon frequency, with an exponent of 0.2, over many decades of frequency. This dependence corresponded to a stretched-exponential relaxation function and was attributed to a dislocation point-defect mechanism. This was not consistent with a self-organized criticality dislocation model.

R.S.Lakes, J.Quackenbush: Philosophical Magazine Letters, 1996, 74[4], 227-32