Journal of Materials Science, Vol.44, No.13, 3420-3427, 2009
Microstructure and mechanical properties of an Al-Ni-Co intermetallics reinforced Al matrix composite
A new intermetallic particle reinforced metal matrix composite was produced from pure Al and 15 wt% Al72Ni12Co16 quasicrystalline particles by stir-casting method, followed by hot-extrusion. Microstructural analysis of the as-cast composite shows that the Al72Ni12Co16 quasicrystalline phase has transformed to the crystalline phase Al-9(Co, Ni)(2) and an eutectic structure has formed in the Al matrix during the casting process. The particle size of the Al-9(Co, Ni)(2) phase is much smaller than that of the original quasicrystalline particles. After extrusion, the composite has a more uniform distribution of the reinforcement particles and eutectic structure as well as a reduced porosity. Tensile tests indicate that the mechanical properties of the as-cast composite are improved over the matrix properties remarkably, except for the ductility. The strength and ductility of the composite can be improved by the hot-extrusion, while the elastic modulus can be slightly decreased.