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

The fabrication process for Al-TiB 2 nanocomposites, in which TiB 2 nanoparticles were incorporated into aluminum with K 2 ZrF 6 flux-assisted melt stirring, was studied. The microstructure of the Al-TiB 2 nanocomposites was investigated using scanning electron microscopy and transmission electron microscopy. The strengthening effect of TiB 2 nanoparticles on the aluminum matrix was examined by microhardness measurements. Results revealed that TiB 2 nanoparticles were successfully incorporated and dispersed into the aluminum melt in the presence of the K 2 ZrF 6 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 TiB 2 nanoparticles increased the composite hardness by 60, 90, and 150 pct, respectively, when compared to commercial purity aluminum. The role of K 2 ZrF 6 flux agent on the incorporation of nanoparticles into aluminum melt was discussed.