Structural and microstructural properties of in-situ alumina-titania-graphite hybrid nanocomposite via low energy milling

This study was conducted to investigate the effect of variation milling time and compaction pressure on structural and microstructural of in situ Al2O3–TiO2-graphite nanocomposite using powder metallurgy route. Elemental powders of Al2O3 (alumina) TiO2 (titania) and graphite (C) were milled in a low energy mill using 10 mm alumina ball at 15, 30, 45 and 60 hours of milling. Then, the nanocomposite was compacted using cold compaction with 200 to 800 MPa. No new phase formed because the energy was not enough to initiate solid state reaction during milling. Diffusion of graphite into Al2O3 matrix was only obtained after 60 h of milling. The morphology of Al2O3–TiO2-graphite powder become homogenous with increasing milling time while Al2O3 crystallite size was reduced and internal strain was increased. The densification of Al2O3–TiO2-graphite nanocomposite was enhanced with increasing milling time and compaction pressure.