Nanocrystalline aluminum matrix composites were synthesized via hot extrusion of cryomilled 5083 Al (Al-4.59Mg-0.57Mn-0.25Fe in wt.%) blended with amorphous Al85Ni10La5 Powder. The compression yield strength of the as-extruded composite is 813 and 906 MPa for 10 and 20 vol.% Al85N10La5, respectively. The observed thermal stability is discussed in light of the mechanical behavior. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.