Micro structure and hardening of Al-based nanophase composites

Part amorphous-part crystalline Al-Ni-Y alloys can be produced by devitrification of melt-spun fully amorphous alloys. These materials have a novel structure of nanometre-sized crystals of α-A1 in an amorphous matrix and can be regarded as nanophase composites. Devitrified microstructures are studied by X-ray diffraction and transmission electron microscopy. The significant hardening accompanying devitrification is characterised for various heat treatments, and is mainly attributed to the solute enrichment of the remaining amorphous phase. The hardening kinetics are, however, also influenced by the composition uniformity of amorphous matrix.