Micromechanically based stress and strain-rate flow potentials for anisotropic polycrystals

The dissipation of rigid-viscoplastic material behaviour is related to the stress flow potential and its Legendre-Fenchel conjugated strain-rate flow potential. In this paper micromechanically based approximation of these flow potentials, expressed in terms of the deviatoric stresses and strain-rates, is derived from texture measurements. The dual potentials for single face-centered cubic crystals are approximated in terms of Fourier expansion with tensorial texture coefficients. The macroscopic flow stress and strain-rate potentials for an aggregate of polycrystals can be deduced from those of single crystal under the assumption of either homogeneous strain-rate, or homogeneous stress field from the codf measurements. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)