of AA6061 AlNb Composite Powders S. Dibrowska and D. Oleszak* Faculty of Materials Science and Engineering, Warsaw University of Technology, Woaoska 141, 02-507 Warsaw, Poland X-ray di raction, scanning electron microscopy and hardness measurements were applied as experimental methods to investigate the structure and properties of the crystalline amorphous Al-based composites prepared by mechanical alloying and subsequent high pressure high temperature compaction of the powders. It was possible to obtain bulk, fully dense crystalline amorphous composites and the applied compaction technique allowed preservation of amorphous structure in the composite. Addition of amorphous Al60Nb40 phase to AA6061 alloy resulted in signi cant increase of hardness of the composite (120 HV), comparing to pure Al alloy compacted at the same conditions (75 HV).