Fig.10 Influence of grain boundary structure and curvature on grain boundary plastic deformation
(a, b) cyclic migration of 13.5°[1 ˉ10] dislocation-type grain boundary in shear cycling[116] (The red and yellow arrows indicate the directions of GB migration and shear loading, respectively; the insets exhibit geometrical phase analysis (GPA) maps of the vertical normal strain (εyy), demonstrating the dissociation of GB dislocations 1-3, as marked by the light blue rectangles; the zoomed-in TEM image shows the atomistic core structure of dissociated GB dislocations 1 and 2) (c, d) nonuniform migration of 16°[1 ˉ10] curved grain boundary[118] (The curved GB consists of two different arrays of geometrically necessary dislocations colored with light blue and white, respectively; the light blue and white arrows indicate the synergistic migration of two GB segments toward different directions) (e) geometric schematic of 16°[1 ˉ10] curved grain boundary[118] (Different inclinations along a curved 16° with positive and negative grain boundary inclinations (φ), corresponding to clockwise and counter-clockwise rotations, are highlighted with red and blue dashed lines, respectively) (f) statistics of migration rates and shear coupling factors (β = s / m, where s is GB migration distance and m is shear displacement) of low-angle grain boundaries with different misorientations[116] (Both experimental (Exp.) and molecular dynamics (MD) simulation data are shown) (g) inclination-dependent energy profile of 16°[1 ˉ10] tilt GBs[118] (with respect to two different arrays of geometrically necessary GB dislocations with b = 1/2[10 ˉ1] and b = 1/2[101])
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