Accession Number : AD0262300

Title :   INTERNAL FRICTION AND MODULUS BEHAVIOUR OF GAMMA-IRRADIATED NAC1 CRYSTALS

Corporate Author : MINNESOTA UNIV MINNEAPOLIS INST OF TECH

Personal Author(s) : SIVERTSEN,J.M.

Report Date : 17 JUL 1961

Pagination or Media Count : 1

Abstract : The internal friction and modulus of single crystals of NaCl have been measured during the irradiation of the sample by Co-60 gammas. Since the strain amplitude-independent internal friction is at present only explained in terms of the pinned dislocation theory a test of the theory is important. Time dependence of the decrement and modulus as a useful criterion for the validity of the theory was investigated. This follows from the loop length dependence of the decrement and delta E/E. The generation of point defects during gamma irradiation results in the pinning of dislocation loops of the network due to the interaction between the point defects and dislocations. The experimental results of this study seem to indicate that the loop-length dependence predicted by the pinned-dislocation model is the one observed for the modulus defect and deterion for the validity of the theory was investigated. This follows from the loop length dependence of the decrement and delta E/E. The generation of point defects during gamma irradiation results in the pinning of dislocation loops of the network due to the interaction between the point defects and dislocations. The experimental results of this study seem to indicate that the loop-length der pendence predicted by the pinned-dislocation model is the one observed for the modulus defect and deterion for the validity of the theory was investigated. This follows from the loop length dependence of the decrement and delta E/E. The generation of point defects during gamma irradiation results in the pinning of dislocation loops of the network due to the interaction between the point defects and dislocations. The experimental results of this study seem to indicate that the loop-length dement. (Author)

Descriptors :   *INTERNAL FRICTION, AMPLITUDE MODULATION, ATTENUATION, CHLORIDES, CRYSTAL LATTICES, CRYSTAL STRUCTURE, CRYSTALS, DAMPING, DEFORMATION, FREQUENCY MODULATION, FRICTION, GAMMA RAYS, MEASUREMENT, MODULATION, DAMAGE, RADIATION EFFECTS, SHEAR STRESSES, SINGLE CRYSTALS, SODIUM COMPOUNDS, STRESSES, VIBRATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE