Irradiation creep by dislocation glide enabled by preferred absorption of point defects-theory and experiment

Creep by climb-enabled glide of dislocations may be calculated by mathematically specifying both the origin of the net point defect flux producing the climb and the mode of glide deformation. In general, the net flux contains components arising from (1) differences in point defect capture efficiencies among dislocations and other types of sinks such as cavities, and (2) from differences in capture efficiencies among dislocations whose Burgers vectors are at different orientations with respect to the stress direction. Proposed models based on the first component and employing several modes of glide deformation are reviewed. The characteristics of creep based on the second component, stress induced preferred absorption of point defects on dislocations and subsequent glide, PAG-creep, are described for one mode of glide deformation. Effects of point defect trapping at impurities on creep by this mechanism and on the corresponding climb component of creep are evaluated. Comparison is made with experimental data from light-ion irradiation. The sensitivity of predicted creep rates to the detailed microstructure is emphasized. (orig.)