Accession Number : AD0629557

Title :   A TEST OF VISCOUS DISLOCATION DAMPING THEORY,

Corporate Author : BALLISTIC RESEARCH LABS ABERDEEN PROVING GROUND MD

Personal Author(s) : Flore,Nicholas F.

Report Date : OCT 1965

Pagination or Media Count : 26

Abstract : The amplitude-independent dislocation damping of a series of dilute copper-germanium single crystals has been studied as a function of composition and frequency. The measurements have been performed at room temperature on annealed and gamma-irradiated single crystals driven in longitudinal resonance at 80 and 240 kilocycles per second by means of the Marx piezoelectric oscillator. The results indicate that the Granato-Lucke viscous damping analysis cannot account for the observed magnitude and composition dependence of the damping, although the damping is proportional to frequency in agreement with the theory. They further show that a gamma-ray dose of 2 x 10 to the 8th rads is sufficient to suppress the damping to a composition-independent value of 1 x 10 to the minus 4 which does not decrease with further irradiation. There is evidence that the total damping consists of a composition-dependent edge dislocation loss superposed on a composition-independent screw dislocation loss. (Author)

Descriptors :   (*CRYSTAL DEFECTS, DAMPING), (*SINGLE CRYSTALS, CRYSTAL DEFECTS), COPPER, GERMANIUM, INTERNAL FRICTION, DAMAGE, RADIATION EFFECTS, VISCOSITY

Subject Categories : Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE