Effect of Pressure on Dislocation Damping in Aluminum Crystals

概要

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Attenuation of megahertz ultrasound has been measured in an aluminum crystalunder hydrostatic pressure at room temperature. From the pressure dependence of attenuation at various sound frequencies, the pressure dependence of damping constantfor dislocation motion was determined by an analysis based on the overdampedresonance theory of dislocation. Specimen used was primarily zone-refined 99.9999%Al single crystal containing 1 ppm of Si as impurities. The specimen was irradiated byneutrons and 2-4 ppm of Si atoms were further introduced by a nuclear reaction. Thespecimen was also heat-treated in various ways. Thus the amount and state of impuri-ty atoms were altered, and the high pressure experiments were made for the specimenin different states. The pressure dependence of damping constant was found to bevery sensitive to the state of impurities. The order of magnitude and even the sign ofthe dependence were different for different impurity states. A qualitative discussionwas given to interpret the experimental results.
社団法人日本物理学会の論文
1986-04-15