Accession Number : AD0480978

Title :   AMPLITUDE DEPENDENT INTERNAL FRICTION OF SODIUM CHLORIDE.

Descriptive Note : Interim technical rept. no. 1,

Corporate Author : IOWA STATE UNIV OF SCIENCE AND TECHNOLOGY AMES

Personal Author(s) : Fehr, G. K. ; McGee, Thomas D.

Report Date : 06 APR 1966

Pagination or Media Count : 42

Abstract : The amplitude dependent internal friction of sodium chloride was measured by the composite oscillator technique. Relationships between internal friction, strain amplitude, dislocation density, grain size and impurities were measured between 23 and 300 C. Grain boundaries and impurities pinned the dislocations. Increasing the strain amplitude, temperature and the number of free dislocations increased the internal friction. A large internal friction increase occurred at approximately 65 C for the purest salt. This may be useful in interpreting brittle-ductile transition. Small angle grain boundaries formed in single crystals subjected to relatively low oscillating stresses and temperature. Amplitude dependent internal friction is shown to be dependent upon dislocation generation which does not conform to the Granato-Lucke-Koehler theory. The Granato-Lucke equation was modified to fit the experimental data and to represent the dislocation generation mechanism. (Author)

Descriptors :   *CHLORIDES), *SINGLE CRYSTALS), (*SODIUM COMPOUNDS, (*INTERNAL FRICTION, STRAIN(MECHANICS), DEGRADATION, OSCILLATORS, VIBRATION, CRYSTAL STRUCTURE, GRAIN SIZE, ETCHED CRYSTALS, GRAIN BOUNDARIES, IMPURITIES, BRITTLENESS, DUCTILITY, CRYSTAL DEFECTS, TRANSITION TEMPERATURE, IONS, DAMPING, SPECIAL FUNCTIONS(MATHEMATICAL), DENSITY, SPECTROSCOPY, EXPERIMENTAL DATA, GRAPHICS, TABLES(DATA), STRESSES.

Subject Categories : Crystallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE