Review of internal friction due to point defects

Simple considerations lead to the expectation that point defects will cause internal friction (by a stress-induced ordering mechanism) in all cases where the introduction of the defects sets up local asymmetric distortions of the surrounding lattice. Three categories of specific examples are considered, in which the relaxation centers are believed to contain 1. (a) a single isolated elementary point defect, 2. (b) two interacting elementary point defects, 3. (c) several interacting elementary point defects. The elementary point defects considered are 1. (1) an interstitial solute atom, 2. (2) a substitutional solute atom, 3. (3) a vacancy, 4. (4) a split self-interstitial. The material for this review is taken from the existing literature with the exception of a brief account of some recent experiments by the author on cold-worked nickel, which relate to the report of a peak due to split interstitials in this metal by Seeger et et al.(17). Due to a background recovery phenomenon, it was not found possible to obtain support for the existence of the peak. © 1962.