  The role of heterogeneity in the plastic flow of thin ferrite specimens is
investigated in this study. This is done through a recently introduced quasi-2D
experimental-numerical framework that allows for a quantitative comparison of
the deformation fields of metal microstructures between experiments and
simulations at a high level of detail and complexity. The method exploits
samples that are locally ultra-thin ("2D") and hence have a practically uniform
microstructure through their thickness. This allows testing more complex
loading conditions compared to uniaxial micromechanical experiments while
avoiding the complexity of an unknown subsurface microstructure, which limits
comparisons between experiments and simulations in traditional integrated
approaches at the level of the polycrystalline microstructure. The present
approach enables to study the effect of microstructural features such as grain
boundaries. To study the role of stochastic fluctuations, a constitutive model
is employed which introduces random heterogeneity into a crystal plasticity
model. A detailed analysis of the simulations is performed at the level of
individual slip systems. Since both experimental and numerical results are
susceptible to stochastic fluctuations, the outcomes of many simulations are
compared to the experimentally obtained result. This comparison allows us to
determine how a single experiment relates to an ensemble of simulations.
Additionally, results obtained with a conventional crystal plasticity model are
considered. The analysis reveals that the heterogeneity in the plasticity model
is essential for accurately capturing the deformation mechanisms.
