“…Specifically in nickel-based superalloys, prior studies by Villechaise et al and Larrouy et al theorize that areas where localized slip impinges on a neighboring grain boundary, but the slip cannot transmit into the neighboring grain, are favorable crack initiation sites due to the slip shearing the physical grain boundary [6,7]. A recent high-resolution deformation study by Stinville el al on the Inconel-718 nickel-based superalloy furthered these findings by coupling two-dimensional electron backscatter diffraction (2D-EBSD), an microscopic orientation field measurement, and heaviside digital image correlation (H-DIC), a microscopic strain field measurement, to spatially correlate the same slip impingement behavior with plumes of intense intragrain lattice rotation (up to 10 • ), termed microvolumes, as shown in Figure 1 [6][7][8][9][10][11]. These observations, when combined with the crack initiation theory above, provide microvolumes as measurable features that may indirectly identify grains with the most potential for initiating a fatigue crack.…”