Strength and strain hardening of aluminum matrix composites with randomly dispersed nanometer-length fragmented carbon nanotubes

Carbon nanotube (CNT)-reinforced aluminum composites were fabricated through ball milling combined with rolling. The composites exhibit high strength and high strain-hardening ability, the combination of which has been rarely reported. During the ball-milling process, CNTs were broken and became low aspect ratio tubes. The processed composites had the CNTs (a few dozen nanometers in size) randomly and uniformly dispersed in their grain interiors. This type of CNT distribution contributed to work hardening and strengthening by the Orowan mechanism.