Role of microstructure and micromechanics in galvanic corrosion
July 15-20, 2018
Present modeling approaches for galvanic corrosion include theories based on mechanics (relying on stress-state and deformation as the driving force for corrosion) and chemistry (relying on local chemical potentials for the basis of a galvanic reaction), although a unifying platform or set of experiments is needed to directly compare these two methods. In the present work, a set of experiments are conducted that combine chemistry and mechanics approaches in conjunction with simulations of the underlying mechanical behavior of the materials, and the results are used for statistical analyses to view correlations between these disparate techniques. This work includes detailed characterization of the material’s grain structure via electron backscatter diffraction (EBSD) and constitutive particles through energy dispersive spectroscopy (EDS), followed by creation of strain maps relative to the microstructure during loading from digital image correlation (DIC), and subsequent galvanic corrosion as spatially measured from a confocal microscope or optical profilometry. As shown in Fig. 1, this is performed spatially across the same region of interest on a specimen. Detailed statistical analyses, based on Gaussian Process modeling, are used to identify spatial locations of corrosion relative to microstructural features and high strain.
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Michael Sangid, Andrea Nicolas, and Alberto Mello, "Role of microstructure and micromechanics in galvanic corrosion" in "Stress-Assisted Corrosion Damage V", A.K. Vasudevan, ONR (retired) Ronald M. Latanision, Exponent, Inc. N. J. Henry Holroyd, Luxfer Eds, ECI Symposium Series, (2018). http://dc.engconfintl.org/sacd_v/13