A Review of: Theory of Dislocations, Third Edition, Peter M. Anderson, John P. Hirth and Jens Lothe, Cambridge University Press, 2017

For nearly 60 years the book “Theory of Dislocations” by John P. Hirth and Jens Lothe has been the authoritative reference on the theory of dislocations. The reputation of the book was that it was not for the feint of heart. Rather it was widely considered to be the authoritative reference to be consulted only after the reader had started with more elementary books on dislocations like “Introduction to Dislocations” by Derek Hull and David J. Bacon or “Elementary Dislocation Theory” by Johannes and Julia R. Weertman. More recently the book by Wei Cai and William D. Nix, “Imperfections in Crystalline Solids” has provided an intermediate introduction to dislocations as a bridge between the more elementary books just cited and the book by Hirth and Lothe, which was written for experienced researchers. Now, with the Third Edition of “Theory of Dislocations,” with Peter M. Anderson as the lead author, the classic book by Hirth and Lothe has been made much more assessible to a wider audience of students and researchers. Without sacrificing any of the rigor found in the first two editions of “Theory of Dislocations,” the Third Edition provides a much more tutorial approach to understanding and appreciating the theory of dislocations.

A research on the mechanism and model of surface micro-damage in grinding hardening

Grinding hardening can obtain hardening effect besides fine machining effect on the surface of workpiece. A certain degree of surface micro-damage will be formed during grinding hardening process which mainly contains micro-crack, melting coating, decarburization, and surface scratch. In order to study the micro-damage of grinding hardening, the paper carries on a grinding hardening experiment and the characteristics of micro-damage are observed. The generation mechanism of micro-crack is revealed. It is formed by the accumulation of dislocation pile-up in the condition of grinding hardening process. When the grinding depth reaches a certain value, the surface micro-crack will be produced obviously and become more serious with the increasing of grinding depth. Other micro-damage containing surface melting coating, decarburization, and surface scratch are also studied and their relevance with micro-crack is revealed. Based on the grinding hardening theory and pile-up dislocation theory, a model for micro-crack of grinding hardening is established. The calculating result of the model accords with the experimental result in general.

Identification of grown-in dislocations in protein crystals by digital X-ray topography

X-ray topography is a useful and nondestructive method for direct observation of crystal defects in nearly perfect single crystals. The grown-in dislocations from the cross-linked seed crystal in tetragonal hen egg-white lysozyme crystals were successfully characterized by digital X-ray topography. Digital X-ray topographs with various reflections were easily obtained by reconstruction of sequential rocking-curve images. The Burgers vector of the dislocation is different from those reported previously. Interestingly, one of the dislocations had a bent shape. The preferred direction of the dislocation line was analysed by the estimated dislocation energy based on the dislocation theory. The dislocation energy can be estimated by the dislocation theory even in protein crystals composed of macromolecules.