Mechanical elastic constants and diffraction stress factors of macroscopically elastically anisotropic polycrystals: the effect of grain-shape (morphological) texture

• Published in: Philosophical magazine (Abingdon, England) England), 2004-11, Vol.84 (33), p.3547-3570
• Main Authors: Koch, N., Welzel §, U., Wern, H., Mittemeijer, E.J.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Elasticity, elastic constants; Exact sciences and technology; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Physics
• ISSN: 1478-6435; 1478-6443
• DOI: 10.1080/14786430412331284504

The effect of the grain-shape ('morphological') texture of a polycrystal on the mechanical elastic constants and diffraction (X-ray) stress factors is investigated. To this end, the Eshelby-Kröner grain interaction model originally devised for polycrystals consisting of spherical grains is extended to ellipsoidal grain morphology. Results obtained for the mechanical elastic constants show that a polycrystal consisting of ellipsoidal grains with their principal axes aligned along common directions (i.e. when an ideal grain-shape texture occurs) is macroscopically elastically anisotropic. Also the diffraction (X-ray) stress factors are affected by the grain-shape texture; they reflect the macroscopic elastic anisotropy by resulting in nonlinear so-called sin 2  ψ plots. In general, a grain-shape texture can have a moderate effect on the mechanical elastic constants and a pronounced effect on the diffraction elastic constants, depending on the crystal symmetry and single-crystal elastic anisotropy.