Copyright © 2014 The Minerals, Metals & Materials Society. All rights reserved. Aluminum-matrix nano-composites have been produced after incorporating various hard ceramic nanoparticles (Al2O3, AIN and SiC) and Al2O3 microparticles into liquid metal by mechanical stirring. The mechanical stirring process is optimized to obtain distribution of nanoparticles in entire volume of the liquid. However, locally, nanoparticle clusters have been found. Application of the ultrasound to the slurry containing nanoparticles resulted in significantly improved particle dispersion and reduced nanoparticle clusters density. Nano-composites have been characterized by optical and scanning electron microscopy to see dispersion enhancement. Hardness was measured to study the local mechanical properties of these composites. ExoMet Project, which is co-funded by the European Commission in the 7th Framework Program (contract FP7-NMP3-LA-2012-280421), by the European Space Agency and by the individual partner organizations.