In-situ Al-based bulk nanocomposites by solid-state aluminothermic reaction in Al–Ti–O system

The paper reports the study on the synthesis and characterization of nanocomposites reinforced with in-situ intermetallic compounds via mechanical–thermal activation. The Al matrix bulk hybrid nanocomposites are synthesized by an aluminothermic reduction reaction between the nanocrystalline Al and TiO2 powder blends. The nanocrystalline powder mixture of Al and TiO2 is synthesized by high-energy ball milling. The milled powders are characterized by differential thermal analysis (DTA), X-ray diffraction (XRD) and electron microscopy. The powder compacts after thermal treatment are characterized by XRD and electron microscopy. The microhardness of the in-situ composite is in the range 3.4–4.2 GPa and it is probably attributed to the nanosized reinforcements and ultrafine grain structure of the Al matrix. A suitable combination of the mechanical milling and thermal treatment can lead to the synthesis of Al-based nanocomposites by the solid-state processing route for the present system.