Theoretical and molecular dynamics analyses of a confined crack under mode-II shear loading in a simple thin-strip geometry revealed that two universal intrinsic material length-scales controlled the mechanism of plastic deformation in single nanocrystals under geometrical confinement. These two length-scales controlled the occurrence of complete dislocation, partial dislocation and no-dislocation nucleation from defects. The results explained earlier experimental and computational observations that had revealed a change in the deformation mechanism under geometrical confinement. That was illustrated here in a specific simple geometrical set-up which revealed the governing physical mechanisms of plasticity under extreme geometrical confinement.

Crystal Size Controlled Deformation Mechanism - Breakdown of Dislocation Mediated Plasticity in Single Nanocrystals under Geometric Confinement. D.Sen, M.J.Buehler: Physical Review B, 2008, 77[19], 195439