Print Email Facebook Twitter Influence of dislocations on the apparent elastic constants in single metallic crystallites Title Influence of dislocations on the apparent elastic constants in single metallic crystallites: an analytical approach Author van Dokkum, J.S. (TU Delft Team Kevin Rossi) Bos, C. (TU Delft Team Kevin Rossi; Tata Steel) Offerman, S.E. (TU Delft Team Erik Offerman) Sietsma, J. (TU Delft Team Kevin Rossi) Date 2021 Abstract Intricate knowledge of dislocation networks in metals has proven paramount in understanding the constitutive behaviour of these materials but current experimental methods yield limited information on the characteristics of these networks. Recently, the isotropic anelastic response of metals has been used to investigate complex dislocation networks through the well-known phenomenon that the observed elastic constants are influenced by dislocations. Considering the dependence of the behaviour of a Frank-Read (FR) source on its initial dislocation character and using discerning characteristics of dislocations, i.e. Burgers vector, line sense and slip system, the present paper takes dislocation character, crystal structure and dislocation network geometry into account and obtains the anisotropic mechanical response for a generic Poisson's ratio. In this work, the tensile test tangent moduli and yield points are presented for spatially uniform and nonuniform dislocation distributions across slip systems. First, the reversible shear strain of the FR source is derived as a function of initial dislocation character. The area swept by a mobile and initially straight dislocation segment pinned at both ends is given as an explicit function of the line stress. Secondly, the anisotropic anelastic strain contribution of FR sources to the total pre- and at-yield strain in single crystallites is calculated. For a given normal stress and superposition of the principal infinitesimal linear elastic lattice strain and anelastic dislocation strain, the tangent moduli are presented. The moduli and the inception of plastic flow have a notable dependence on initial dislocation character, spatial dislocation distribution and loading direction. Subject Analytical modellingDislocation loopDislocation structureElastic constantsTensile behaviour To reference this document use: http://resolver.tudelft.nl/uuid:c6bd5a97-3111-406e-bb66-b90ced55a0d6 DOI https://doi.org/10.1016/j.mtla.2021.101178 Source Materialia, 20 Part of collection Institutional Repository Document type journal article Rights © 2021 J.S. van Dokkum, C. Bos, S.E. Offerman, J. Sietsma Files PDF 1_s2.0_S2589152921001812_main.pdf 6.73 MB Close viewer /islandora/object/uuid:c6bd5a97-3111-406e-bb66-b90ced55a0d6/datastream/OBJ/view