Quantitative Atomic Force Microscopy Characterization and Crystal Plasticity Finite Element Modeling of Heterogeneous Deformation in Commercial Purity Titanium

Using a four-point bend sample of commercial purity titanium deformed to a surface strain around 1.5 pct, the active dislocation slip and twin systems in a microstructural patch of about 15 grains were quantitatively analyzed by a technique combining atomic force microscopy (AFM), backscattered electron (BSE) imaging, and electron backscattered diffraction (EBSD). Local shear distribution maps derived from z-displacement data measured by AFM were directly compared to results of a crystal plasticity finite element (CPFE) simulation that incorporates a phenomenological model of the deformation processes to evaluate the ability of the CPFE model to match the experimental observations. The CPFE model successfully predicted most types of active dislocation slip systems within the grains at correct magnitudes, but the spatial distribution of strains within grains differed between the measurements and the simulation.