Mesoscale mechanics behavior in materials deformation inferred from digital image correlation measurements

Perhaps the best definition of digital image correlation (DIC) appears in the recent book “Image Correlation for Shape, Motion and Deformation Measurements” by Sutton et al. [1]: “Digital image correlation refers to the class of non-contacting methods that acquire images of an object, store images in digital form and perform image analysis to extract full-field shape, deformation, and/or motion measurements.” Over the past two decades, DIC has arguably become the premier tool for deformation measurement in materials science and engineering. Thanks to considerable advances in instrumentation and computer algorithms, DIC is now capable of proving a vast amount of information about length-scale dependent processes in materials deformation that span length scales ranging from the mesoscale to the continuum. This information is being used to construct more physically meaningful constitutive models of deformation and fracture, guide material applications, and provide a pathway for new materials designs. In this presentation, we will consider some examples where inferences about mesoscale behavior in materials deformation can be drawn from DIC measurements. After a short review of DIC basics, we will investigate: (a) the Portevin–Le Châtelier effect, a material instability related to dynamic strain gaining and dislocation/solute interactions, in steel and aluminum alloys; (b) measurement of strain-induced transformation kinetics in TRIP steel using a technique that combines DIC with neutron diffraction; (c) two examples where DIC has been used to infer mesoscale processes during fracture; (d) microstructural banding during biaxial deformation; (e) propagative instabilities in a rare earth containing Mg alloy and the role of twin/dislocation interactions; (f) Li diffusion effects on strain in a battery anode material. The presentation will conclude wit+D233h the speaker’s thoughts on where DIC technology is headed in the future. REFERENCE [1] Sutton, M.A., Orteu, J.-J., Schrier, H.W. Image Correlation for Shape, Motion and Deformation Measurements. Basic -Concepts, Theory and Applications. New York, NY: Springer, 2009