Solid state sintering and high temperature compression properties of Al-alloy5000/AlN nanocomposites

Nanocomposites of Al-alloy5000 reinforced with 4-30 vol.% ceramic phase (ox ides and aluminium. nitride particles) were produced by cryomilling and hot pressing. Diffusion mechanisms occurring during the intermediate stage of sintering were analysed by a kinetic study at constant rates of heating. Th e fine and homogeneous dispersion of the ceramic phase in the Al matrix giv es the composites a stable nanostructure and influences the diffusion mecha nisms (volume or grain boundary). High temperature compression behaviour of the nanocomposites was then examined. In the chosen conditions of temperat ure and strain rates (823 K, 10(-3)-2.7 s(-1)), the materials exhibit a hig h resistance to compression. However, after extrusion of a composite contai ning a low quantity of ceramic phase, deformation by superplasticity occurs . (C) 2001 Elsevier Science B.V. All rights reserved.