Nanoscale twin boundaries were recently reported to be capable of enhancing the fracture toughness of nanocrystalline (nc) metals. The present study aims to investigate the toughening effects of nanoscale twin boundaries in nc Ni by using molecular dynamics simulation. It was shown that the presence of embedded nanoscale twin boundaries facilitates the accommodation of dislocations through partial dislocation motion along twin boundaries, resulting in improved fracture toughness. Moreover, crack propagation was observed to be intragranular in a nanotwinned sample, concurrent with nucleation of nanovoids in the intersections of twin boundaries and grain boundaries.

The Effect of Nanoscale Twin Boundaries on Fracture Toughness in Nanocrystalline Ni. H.Zhou, S.Qu: Nanotechnology, 2010, 21[3], 035706