The effect of strain heterogeneity on the work hardening of polycrystals predicted by mean-field approaches

In polycrystalline aggregates deforming by crystal plasticity, the local shears on each slip system can be significantly affected by the intergranular interaction. Therefore, in the framework of mean-field approaches, the intragrain strain heterogeneity must be taken into account when dealing with microstructure evolution associated with strain hardening. For that goal, a novel treatment is proposed and applied to a two-dimensional linearly viscous polycrystal. The results of the implementation of this new hardening treatment within the self-consistent scheme are compared to those of a fast Fourier transform-based full-field computation, considered as a reference solution. It is shown that the evolution with strain of the grain average reference resolved shear stress (RRSS) is well reproduced by the proposed scheme. The overall stress response of the polycrystal is slightly underestimated, due to some intrinsic heterogeneity of the distribution of RRSS.