AMPLITUDE DEPENDENT INTERNAL FRICTION OF SODIUM CHLORIDE.
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 06, 1966
- Accession Number
- AD0480978
Entities
People
- G. K. Fehr
- Thomas D. Mcgee
Organizations
- Iowa State University