Fig.2 Schematics of grain boundary model and disconnection geometry
(a-d) double crystal lattice with a Σ5 [100] symmetric tilt grain boundary and its CSL lattice[7] (The Burgers vectors of DSC dislocations are indicated by the blue arrows in Figs.2b and c, and CSL-based DSC lattice model is shown in Fig.2d. STGB—symmetric tilt grain boundary;CSL—coincidence-site lattice;q —translation vector, which connects one black lattice point to its nearest white lattice point; DSC—displacement shift complete)
(e) structure units of different <110> symmetric tilt grain boundaries in Cu[11] (Σ1(001) grain boundary (single crystal) only contains A structure units; Σ11(113) grain boundary is composed of C structure units; Σ27(115) grain boundary, across which the tilt angle is between the above two grain boundaries, is comprised of A, B, and C structure units; Σ3(111) grain boundary, namely coherent twin boundary, is constructed by sequential D structure units; a—lattice constant) (f, g) geometric structures of grain boundary disconnections[15] (μ, λ—neighboring grain; h—step height; b —Burgers vector; f —Frank vector; t —translation vector) (h, i) different configurations on the same grain boundary[7] ( b1—Burgers vector of the disconnection; there are multiple possible step heights corresponding to a disconnection with b1, and the step height can be h1j = (1 + 5j)az, where j is integer and az is the size of the DSC unit cell; h10—step height with az; —step height with 4az)
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