The mean free path length of dislocations plays an important role in the plastic behavior of metals, which may be significantly enhanced by the addition of nanoparticles. The effects of particle distribution pattern, particle size, shape and volume fraction on the dislocation mean free path length and average obstacle distance are analyzed in two- and three-dimensional models. As the particle volume fraction increases, the dislocation mean free path length and average distance between dislocations obstacles can be significantly reduced, implying enhancement of strength. The random particle distribution exhibits the best combination of dislocation mean free path length and average obstacle distance. In addition, both dislocation mean free path and average obstacle distance can be significantly reduced by changing the particle shape from nanosphere to nanorod. The present analysis may provide useful information for designing the particle enforced composite materials. © 2006 Elsevier Ltd. All rights reserved.
Bibliographical noteWe acknowledge support by the Academic Quality Fund from Columbia University, and a MRSEC Seed Grant from Columbia MRSEC NSF No. DMR-0213574, and also from NSF-CMS-0134226 and NSF-CMS-0407743.