Effect of particle dispersion on the mechanical behavior of Al-based metal matrix composites reinforced with nanocrystalline Al-Ca intermetallics

Al-based metal matrix composites reinforced 20 and 40 vol.% of Al-Ca intermetallic particles have been produced by powder metallurgy. Two distinct approaches have been used for the dispersion of the reinforcing particles within the Al matrix: manual blending and ball milling. Manual blending leads to the agglomeration of the Al-Ca particles to form a cell network throughout the consolidated sample. On the other hand, the composites prepared by milling display a more homogeneous distribution of the reinforcing particles. This has a strong impact on the mechanical properties. The strength increases from 112 MPa for pure Al to 140 and 165 MPa for the blended composites with 20 and 40 vol.%, while the strength increases to 250 and 280 for the corresponding composites produced by milling. This behavior is linked to the reduced matrix ligament size characterizing the milled composites. (c) 2011 Elsevier B.V. All rights reserved.