Signatur:
ZSP-202-243
In:
Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command, 243
Beschreibung / Inhaltsverzeichnis:
The internal friction of single-crystal ice has been attributed to reorientation of the water molecule under periodic stress. However, the theory for damped dislocations, which offers another mechanism for the internal friction of ice, has not been investigated. The effects of scratching the surface of 41 ice samples and X-irradiating and plastically deforming them were evaluated. The effects observed on the internal friction of pure, single-crystal ice, in the flexure mode of oscillation between 400 and 1400 Hz, supported the existence of a dislocation-controlled mechanism, with the drag produced by the interaction of the dislocation with the protons in the crystal. In addition, analysis of the detailed shape of the data curve showed two peaks of tan delta as a function of temperature. The second peak, which had not been previously reported, had an activation energy of 0.16 eV and a relaxation time of 1.7 x 10^8 sec at infinite temperature. These experiments indicated that both peaks vrere controlled by the dislocation mechanism described above.
Materialart:
Schriftenreihen ausleihbar
Seiten:
iv, 41 Seiten
,
Illustrationen
Serie:
Research report / Cold Regions Research and Engineering Laboratory, CRREL, US Army Material Command 243
URL:
http://hdl.handle.net/11681/5931
Sprache:
Englisch
Anmerkung:
CONTENTS: Introduction. - Previous work. - Previous theory. - Internal friction of a crystal. - Granato-Lücke theory of dislocation damping. - Double kink mechanism. - Mechanisms not involving dislocations. - Experimental work. - Experimental approach. - Experimental apparatus. - Mode of oscillation. - Automated system. - Support, acoustic isolation, and temperature control. - Sample preparation. - X-ray apparatus. - Data analysis. - Stage I. - Stage II. - Stage III. - Experimental results and discussion. - The second peak. - Interpretation of scratching, X-irradiation, and plastic deformation. - Scratching. - X-irradiation. - Plastic deformation. - Supporting research. - Interpretation of the two peaks. - Conclusions. - Literature cited. - Appendix A: Computer programs. - Abstract.
Standort:
AWI Archiv
Zweigbibliothek:
AWI Bibliothek
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