Stage III dislocation pinning in silver resulting from gamma irradiation

The objectives of this work were fourfold: (1) to test the validity of the vibrating string dislocation model in silver, (2) to determine in which annealing stage long-range migration first occurs, (3) to measure the migration energy and identify the defect responsible for observed annealing, and (4) to investigate the possibility of dislocation pipe diffusion. Apparatus is described which is capable of continuously measuring changes in the elastic modulus and internal friction during gamma irradiation over the temperature range from less than 40K to well above room temperature. A novel hollow-cylinder sample geometry permits use of a source strength of only 1 Ci. Survey experiments over a wide temperature range and isothermal irradiations above room temperature are discussed. The results are explained in terms of the Koehler-Granato-Lucke vibrating string dislocation model and the Thompson-Buck-Huntington-Barnes defect-dislocation interaction model. (auth)