An Investigation of the Use of Ni3Al Intermetallic Compound for Fabrication of Al Matrix Composites

Fabrication and characterization of aluminum matrix composites containing different volume fractions of Ni3Al powder (5-40 Vol%) were investigated. Ni3Al powder was produced by mechanical alloying of elemental nickel and aluminum powder mixture. Al-Ni3Al composite parts were prepared using a powder metallurgy route involving two stages Al and Ni3Al powder mixtures were first compacted under 500MPa and then hot-pressed under 250MPa at 420 oC for 10min. The microstructure and hardness of consolidated parts were investigated by x-ray diffractometery, optical and scanning electron microscopy and hardness measurements. Results showed that consolidated Al-Ni3Al samples included no significant porosity with a nearly uniform distribution of Ni3Al particles. Additionally, structural examinations showed that no significant reaction between Ni3Al and aluminum matrix occurred during sintering process. Al-Ni3Al composites exhibited a higher hardness value compared with pure aluminum sample prepared under identical conditions. The hardness value of Al-Ni3Al composites increased linearly as Ni3Al content increased.