Fabrication of Al-TiB₂ Nanocomposites by Flux-Assisted Melt Stirring

The fabrication process for Al-TiB₂ nanocomposites, in which TiB₂ nanoparticles were incorporated into aluminum with K₂ZrF₆ flux-assisted melt stirring, was studied. The microstructure of the Al-TiB₂ nanocomposites was investigated using scanning electron microscopy and transmission electron microscopy. The strengthening effect of TiB₂ nanoparticles on the aluminum matrix was examined by microhardness measurements. Results revealed that TiB₂ nanoparticles were successfully incorporated and dispersed into the aluminum melt in the presence of the K₂ZrF₆ flux during mechanical stirring. In the as-cast microstructure, most nanoparticles segregated in the interdendritic regions as a result of particle redistribution during solidification. The addition of 2, 5, and 10 wt pct TiB₂ nanoparticles increased the composite hardness by 60, 90, and 150 pct, respectively, when compared to commercial purity aluminum. The role of K₂ZrF₆ flux agent on the incorporation of nanoparticles into aluminum melt was discussed.