Internal Friction at Low Temperature in High Purity Magnesium

Abstract

Ultra pure magnesium exhibits at very low temperatures an interesting new damping phenomena after plastic deformation. A peak II1 appears at 15 K in the cycle range, after annealing at 270 K. This peak is attributed to an interaction between geometrical kinks and vacancy‐type defects created by cold‐work or irradiation. In the kilocycle experiments, a new peak D1 appears between 11 and 22 K. This peak is connected to a thermomechanical unpinning of kinks from vacancies or impurities. This peak is probably related to the decrease of internal friction in the cycle range between 10 and 30 K.