A transmission electron microscopy study of the dislocation distribution under an indentation has revealed first that a complex sequence of loop nucleation, cross-slip and renucleation results in a cross-like network at the free surface and a square-like network underneath. These dislocation distributions are made up of two types of dislocation: redundant dislocations responsible for general plasticity and work hardening, and shielding dislocations responsible for the equilibrium of forces. The former are roughly an order of magnitude more prevalent. The total number of dislocations are consistent with continuum plasticity theory while the shielding density is consistent with a proposed superdislocation pile-up model.
|Original language||English (US)|
|Number of pages||17|
|Journal||Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties|
|State||Published - Nov 1995|
Bibliographical noteFunding Information:
ACKNOWLEGMENTS This research was supported by the University of Minnesota Corrosion Center and Department of Energy, Basic Energy Sciences Grant No. DE-FC02-88ER45337-AOOS for one of us (H.H.) and by Basic Energy Sciences Grant No. DE-FG02-84ER45141 for two of us (W.Z. and W.W.G.). One of us (S.V.) would like to acknowledge the support by the Center for Interfacial Engineering under Grant No. NSF/CDR-8721551. Another of us (W.Z.) wishes to acknowledge the creative atmosphere and hospitality of the Department of Materials Science and Engineering at the Warsaw University of Technology, Poland, where part of this work was done.