Ti3AlC2/Al2O3 nanocomposite powder was synthesized by mechanical-activation-assisted combustion synthesis of TiO2, Al and C powder mixtures. The effect of mechanical activation time of 3TiO(2)-5Al-2C powder mixtures, via high energy planetary milling (up to 20 h), on the phase transformation after combustion synthesis was experimentally investigated. X-ray diffraction (XRD) was used to characterize as-milled and thermally treated powder mixtures. The morphology and microstructure of as-fabricated products were also studied by scanning electron microscopy (SEM) and field-emission gun electron microscopy (FESEM). The experimental results showed that mechanical activation via ball-milling increased the initial extra energy of TiO2-Al-C powder mixtures, which is needed to enhance the reactivity of powder mixture and make it possible to ignite and sustain the combustion reaction to form Ti3AlC2/Al2O3 nanocomposite. TiC, AlTi and Al2O3 intermediate phases were formed when the initial 10 h milled powder mixtures were thermally treated. The desired Ti3AlC2/Al2O3 nanocomposite was synthesized after thermal treatment of 20 h milled powder and consequent combustion synthesis and FESEM result confirmed that produced powder had nanocrystalline structure. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.