Table of Contents
Textures and Microstructures
Volume 26–27

Yield Loci Calculation of Hexagonal Materials Using a Selfconsistent Polycrystalline Model

1Instituto de Física Rosario (UNR-CONICET), 27 de Febrero 210 Bis, Rosario 2000, Argentina
2AECL Research, Whiteshell Laboratories, Manitoba R0E 1L0, Canada

Received 8 November 1995

Copyright © 1996 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Polycrystalline models are used for the calculation of the yield loci of hcp aggregates with different crystallographic textures. Predictions are made using both a classical Taylor Full Constraints (FC) approach and a viscoplastic selfconsistent (VPSC) formulation. Typical deformation modes for low and high temperature are assumed to be active. The vertex configuration of the Single Crystal Yield Surface (SCYS) and the relative activity of different deformation modes as a function of the applied stress are also presented and discussed. For low temperature, when twinning is active, a non centro-symmetric behavior is observed in textured polycrystals along the direction of the <c>-axis texture component. Such effect, associated with the directionality of twinning, is well reproduced by the VPSC model. For high temperature, the predicted yield loci are centro-symmetrical but also strongly dependent on the texture of the aggregate.