This work was supported by the UK Engineering and Physical Sciences Research Council.
Critical Thickness Theory Applied to Micromechanical Testing†
Article first published online: 2 MAY 2012
Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Advanced Engineering Materials
Special Issue: Nanostructured Materials
Volume 14, Issue 11, pages 942–947, November 2012
How to Cite
Dunstan, D. J. (2012), Critical Thickness Theory Applied to Micromechanical Testing. Adv. Eng. Mater., 14: 942–947. doi: 10.1002/adem.201200017
- Issue published online: 2 NOV 2012
- Article first published online: 2 MAY 2012
- Manuscript Revised: 12 APR 2012
- Manuscript Received: 13 JAN 2012
Critical thickness theory for the plastic deformation of small stressed volumes is reviewed, with particular emphasis on its application to the size effect in common micromechanical testing methods, foil flexure, wire torsion, and compression and tension of micropillars and wires. Key predictions which distinguish the theory from others are that plasticity initiates throughout a finite volume when a strain-thickness product or strain-volume integral exceeds a critical value related to the Burgers vector; that misfit or geometrically necessary dislocations will generally be found outside this volume; and that the intrinsic or bulk strength of the material is not changed by the size effect. Experiments designed to test these predictions are briefly described.