The orientation dependence of dislocation internal friction in real crystals. II. Hexagonal crystals

The orientation dependence of internal friction (ODIF) in single crystals of Zn, Cd, and Mg is studied. Sets of active slip systems are found in these crystals using internal friction (IF) data. IF is measured by means of composite piezoelectric resonator methods in the kHz region at different temperatures from 20 to 270°C. The damping decrement π is found to πQ−1 where Q is the quality factor of the composite resonator. It is shown that IF as a function of orientation of the specimen has a peak which height and position depend on the temperature. Sets of active slip system are found by means of analysis of ODIF by computer. The relative contributions of different slip systems in total IF are estimated. It is concluded that basic dislocations in single crystals of Mg and Cd are the most active at 200 and 100°C accordingly. [Russian Text Ignored].