Fabrication of TiB2 nanoparticulates-reinforced aluminum matrix composites by powder metallurgy route

摘要

Al/TiB2 nanocomposites were fabricated via powder metallurgy route through a primarily cold isostatic pressing of aluminum powder containing 1.5, 2.5, 3.5, 5, and 10 Vol.% of TiB2 nanoparticles and subsequent sintering at two temperatures of 650? and 680?. Density, phase analysis, microstructure, and compressive strength of the samples were then characterized. Results indicated that with increasing the content of the second phase (TiB2), the amount of structural deteriorations like porosity and crack increases as a result of poorer distribution of ceramic nanoparticles, agglomeration, and retarded sintering. However, the compressive strength of nanocomposites tends to enhance with addition and increasing the amount of reinforcement phase (TiB2). Improvement in the compressive strength of composites is a result of activation of strengthening mechanisms such as formation and pile-up of dislocations. The trend of the compressive strength decreases after reaching a maximum amount for Al-2.5TiB(2), in 680?. Generally, samples with moderate amounts of TiB2 (2.5-5 Vol.%) have shown better microstructural and mechanical characteristics due to efficient impact of strengthening mechanisms with lower negative effects of destructive factors like porosity and agglomeration.