Development of Aluminium Composites Through P/M Route: Case of Nitrides

摘要

In the present study aluminium matrix composites reinforced with differente nitredes have been fabricated and studied. Processing technique was based on a powder metallurgy, route consiting of mixing of powders, cold uniaxial compaction and extrusion. Base aluminium used as matrix was the AA6061 alloy (Al-Mg-Si), together with four different reinforcements in particulate form: TiN, Si_3N4, BN and Li_3N. The study carried out on the composites so produced was focused on microstructural analysis and mechanical and tribological testing. Microstructure of composites presented a good distribution of reinforcements, although some banding have been observed in some samples. Porosity levels was very low, reaching a densification level close to 100%. Strength of composites were higher than the unreinforced matrix in Tl state whereas for T6 state there was not a significant increase. Advantages of composites in terms of tribological properties were only for Si_3N_4 because a very low friction coefficient and for Li_3N for low wear rate.