Multilevel model of polycrystalline materials: grain boundary sliding description

Abstract

View the article online for updates and enhancements. Related contentThree-level modeling of fcc polycrystalline inelastic deformation: grain boundary sliding description P Trusov, E Sharifullina and A Shveykin Abstract. Material behavior description in a wide range of thermomechanical effects is one of the topical areas in mathematical modeling. Inclusion of grain boundary sliding as an important mechanism of polycrystalline material deformation at elevated temperatures and predominant deformation mechanism of metals and alloys in structural superplasticity allows to simulate various deformation regimes and their transitions (including superplasticity regime with switch-on and switch-off regimes). The paper is devoted to description of grain boundary sliding in structure of two-level model, based on crystal plasticity, and relations for determination the contribution of this mechanism to inelastic deformation. Some results are presented concerning computational experiments of polycrystalline representative volume deformation using developed model. IntroductionThere are different approaches within the framework of multilevel and multiscale modeling of material inelastic deformation, based on crystal plasticity, in relation formulation for polycrystal inelastic behavior in the case of large deformation gradients. These models have two main aspects [1]: crystallite behavior description (crystal plasticity model is the basis of this level) and description of transition from crystallite level to macroscopic level. The last aspect is one of the important tasks, which solution could be achieved by different ways.The most popular Taylor -Bishop -Hill models [2] (or Full Constraints (FC) models) are classical statistical models, based on relatively independent consideration mesolevel elements (crystallites, grains, subgrains); integration of mesolevel elements into macrolevel element (representative macrovolume or representative volume of macrolevel) is carried out by using the hypothesis about plastic strain homogeneity (plastic strain rate homogeneity) assumed a priori in all crystallites. It is noted in [1], that more common assumption -generalization of Voigt (Taylor) hypothesis about equality the velocity gradient in each crystallite of polycrystal to macroscopic velocity gradient (

Statistical Crystal Plasticity Model Advanced for Grain Boundary Sliding Description

“…The movement of grain boundary dislocations in the slip plane is considered, and the viscoplastic relation is used to set their average displacement rate. Thus, we write [69] According to the above relations, GBS does not occur for a fine-grained material with a structure prepared for SP at a low homological temperature, and therefore a significant grain boundary hardening may happen due to IDS, which is mainly caused by the boundary effects. At a temperature required for SP, GBS will be active and, according to (6), the critical IDS stresses will decrease.…”

“…The movement of grain boundary dislocations in the slip plane is considered, and the viscoplastic relation is used to set their average displacement rate. Thus, we write [69] ( ) ( )…”