Molecular dynamics simulations were made of the shear–coupled migration behaviour of a Σ17 (530)/[001] symmetrical tilt boundary, in the absence or in the presence of nanocracks lying on the grain boundary plane. The simulations were performed for copper bicrystals at 300K. Shear–coupled migration occurs in both simulated configurations. For the case of a tilt boundary without nanocracks, the observed results were similar to the ones reported elsewhere. However, for the case of the Σ17 (530) boundary presenting nanocracks, shear–coupled migration takes place ahead of the mode II loaded crack tips, but the grain boundary gets pinned by the crack tip. The bulging of the tilt boundary reduces the shear stress on the boundary surface near the tip and hinders mode II crack propagation. The applied stress grows until other deformation mechanisms, such as emission of dislocations from the crack tip vicinity or grain boundary sliding, were activated.

Mode II Loading Behaviour of Intergranular Cracks Lying on a Σ17(530)/[001] Symmetrical Tilt Boundary in Copper. A.Luque, J.Aldazabal, J.M.Martínez–Esnaola, J.G.Sevillano: Physica Status Solidi C, 2009, 6[10], 2107–12