Departmental Papers (MSE)

Document Type

Journal Article

Date of this Version

February 2007


We propose a mesoscopic model that explains the factor of two to three discrepancy between experimentally measured yield stresses of BCC metals at low temperatures and typical Peierls stresses determined by atomistic simulations of isolated screw dislocations. The model involves a Frank-Read type source emitting dislocations that become pure screws at a certain distance from the source and, owing to their high Peierls stress, control its operation. However, due to the mutual interaction between emitted dislocations the group consisting of both non-screw and screw dislocations can move at an applied stress that is about a factor of two to three lower than the stress needed for the glide of individual screw dislocations.


Postprint version. Published in Philosophical Magazine Letters, Volume 87, Issue 2, February 2007, pages 113-120.
Publisher URL:


peierls stress, screw dislocations, mixed dislocations, interactions, Frank-Read sources



Date Posted: 30 March 2007

This document has been peer reviewed.