The effect of carbon nanotubes microstructures on reinforcing properties of SWNTs/alumina composite

Alumina reinforced with 1 wt% single-wall carbon nanotubes (SWNTs) was fabricated by hot-pressing. The fracture toughness of SWNTs/Al2O3 composite reaches 6.40 ± 0.3 MPa m1/2, which is twice as high as that of unreinforced alumina. Nanoindentation introduced controlled cracks and the damage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SWNTs reinforcing mechanisms including CNT pullout, CNT fracture, CNT bridging and crack deflection were directly observed, and the relationship between carbon nanotubes microstructures in the matrix and mechanical properties was also discussed in detailed.