Alumina powder assisted carbon nanotubes reinforced Mg matrix composites

•An approach to prepare CNTs-Al2O3 mixture reinforced Mg composite was proposed.•CNTs were homogeneously dispersed in Mg matrix with the help of alumina ‘vehicles’.•CNTs-Al2O3 reinforced Mg composites show obviously improved mechanical properties.

Mg matrix composites reinforced by carbon nanotubes (CNTs)-Al2O3 mixture, which was synthesized by in situ growing CNTs over Al2O3 particles through chemical vapor deposition (CVD) using Ni catalyst, were fabricated by means of powder metallurgy process, followed by hot-extrusion. By controlling synthesis conditions, the as-grown CNTs over Al2O3 particles possessed high degree of graphitization, ideal morphology, higher purity and homogeneous dispersion. Due to the ‘vehicle’ carrying effect of micrometer-level A2O3, CNTs were easy to be homogeneously dispersed in Mg matrix under moderate ball milling. Meanwhile, Al2O3 particles as catalyst carriers, together with CNTs, play the roles of synergistic reinforcements in Mg matrix. Consequently, the Mg matrix composites reinforced by CNTs-Al2O3 mixture exhibited remarkable mechanical properties.