Study on Improving Damping Capacity of Pure Magnesium by Ultrasonic Impact Treatment

The effect of ultrasonic impact treatment (UIT) on the damping capacity of pure magnesium is revealed in this paper. The results show that after UIT, the metal underwent dynamic plastic deformation, the damping capacity of pure magnesium was greatly improved, however, as the UIT time and current intensity increased, the damping capacity of the impacted samples are decreased. Two internal friction peaks have been obtained in all tested samples, P₁ is considered to be related to the interaction between dislocations and weak pinners, and P₂ is caused by the grain boundaries sliding. After the UIT process, those internal friction peaks shift to a higher temperature, with the peak height decrease. The change in damping capacity is believed to be related to the increase in dislocation density and the number of vacancies and grain boundaries.