Microstructure evolution, slip patterns and flow stress

The development of deformation microstructures in medium to high stacking fault energy fcc metals is reviewed illustrating that the basic microstructural element is a cell block. The elongated cell blocks are defined by extended nearly planar boundaries that lie on special planes and enclose a group of approximately equiaxed cells. This duplex structure persists throughout Stage H-M What is known about the origins of these structures and the role of the slip pattern is reviewed. Taking all the measurable structural parameters with respect to the cell blocks: spacing. misorientation angle, and dislocation density, and assuming additive strength contributions, flow stress predictions are derived from Hall-Petch and dislocation strengthening. These predictions are in good agreement with the stress values and hardening rates observed experimentally. (C) 2001 Elsevier Science B.V. All rights reserved.