| A special mechanism/mode of plastic deformation occurring through stress-driven rotations of low-angle grain boundaries (GBs) near crack tips in nanocrystalline and ultrafinegrained (UFG) materials is theoretically described. It is demonstrated that such rotations of GBs represent energetically favorable processes in wide ranges of parameters characterizing precracked specimens with nanocrystalline and UFG structures. Also, these rotations of GBs in part release high stresses concentrated near crack tips and thus hamper crack growth. |
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