Using nanocrystalline particles of mullite and zirconia respectively with diameters in the range 20–30 nm prepared by a sol-gel route, aluminium metal-matrix composites have been synthesized. A hot pressing technique has been used with temperatures varying from 450–610°C. The vickers hardness values for the composites are found to be substantially higher than that of pure aluminium. An order of magnitude increase in hardness is achieved when Al5Mo phase is grown in the composite.
