Direct observation of carbon nanotube induced strengthening in aluminum composite via in situ tensile tests

In situ tensile tests inside a scanning electron microscope chamber are conducted on spark plasma sintered Al and Al-1 vol.% CNT composites to understand the strengthening and deformation mechanisms due to long (25-30 μm) CNT reinforcement addition. Al-CNT composite shows 40% higher tensile strength, and 65% higher stiffness for mere 1 vol.% CNT addition. The failure occurs by CNT pullout from the matrix, which is directly imaged during the tensile testing. Telescopic sliding of CNT walls is also observed which aids to strengthening.