Mechanical behavior of ultrafine-grained Al composites reinforced with B4C nanoparticles

The influence of nanoscale reinforcement on the mechanical behavior of ultrafine-grained composites was studied. Al 5083 (Al-4.5 Mg-0.57Mn-0.25Fe) composites, with grain size of 115 nm and B4C reinforcement size of 38 nm, were fabricated via cryomilling and consolidation. The result reveals that the presence of nanoparticles enhances strength by interacting with dislocations, while simultaneously retarding grain growth. Furthermore, the nanoparticles-reinforced composite exhibits enhanced plasticity relative to the same material reinforced with micrometric particles. The underlying mechanisms are discussed. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.