A double inclusion homogenization scheme for polycrystals with hierarchal topologies: application to twinning in Mg alloys

• A double inclusion elasto-plastic self-consistent (DI-EPSC) scheme is proposed.
• The new micromechanical topology reveals latent effects induced by twinning.
• Twin internal states strongly depend on their interactions with parent domains.
• Influence of initial twin stress state is shown and discussed.
• Influence of the initial texture on the microscopic fields is studied.

The present work introduces a double inclusion elasto-plastic self-consistent (DI-EPSC) scheme for topologies in which crystals can contain subdomains (i.e. twins, etc.). The approach yields a direct coupling between the mechanical response of grains and their subdomains via a concentration relationship on mean fields derived from both the Eshelby and the Tanaka–Mori properties. The latent effect caused by twinning on the mechanical response is observed on both initially extruded and non-textured Mg alloys. For twinned grains, it is shown that deformation system activities and plastic strain distributions within twins drastically depend on the interaction with parent domains. Moreover, a quantitative study on the coupled influence of secondary slip activities on the material response is proposed.