Aluminum-matrix composites dual-reinforced by TiC/CNTs were fabricated using a combination of mechanical milling and spark plasma sintering (SPS) techniques. Composition, structure and morphology of the samples were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HRTEM). Through TEM, nano-scale uniform distribution of TiC nanoparticles around CNTs was observed. In addition, it was shown that hybridization of TiC nanoparticles with CNTs significantly enhanced the mechanical properties of the dual-reinforced composites. In this regard, improvements of 60% and 33% in nano-hardness as well as 149% and 85% in micro-hardness were achieved by doping 1 wt% TiC/CNT into Al matrix in comparison with pure Al and Al/CNT composite, respectively. Apart from fine ceramic particle strengthening, it was found that CNTs can enhance mechanical properties of Al/CNT composites through their defects, crack-bridging and restriction of dislocations motion. The results showed that the effect of TiC nanoparticles and carbon nanotubes can be considered as a main strengthening mechanism for the dual TiC/CNT reinforced Al composites.

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