Internal friction peaks due to dislocation relaxations in plastically deformed and/or irradiated high-purity α-iron. II. Interpretation

Interpretations of the internal friction peaks α, β1, β2, and γ observed (Part I) in plastically deformed and/or low-temperature neutron-irradiated α-iron are presented. The main component of the-peak α is attributed to the generation of kink pairs on non-screw dislocations, while the γ peak is ascribed to the analogous phenomenon on screw dislocations. β1 is identified with the thermally assisted unpinning of string-like, non-screw dislocations from immobile point defects. A second point-defect-dislocation interaction peak, β2, is ascribed to the dragging of the interstitial-type defects which become mobile at about 230 K by geometrical kinks on screw dislocations. A component α′ of the composite α peak is attributed to the trapping and detrapping of geometrical kinks on non-screw dislocations at immobile point defects.