The strengthening of Al 2 O 3 -Cr 2 O 3 /Cr 3 C 2 nanocomposites has been investigated using nano-indentation technique. These composites are fabricated by metal-organic chemical vapor deposition using Cr(CO) 6 as a precursor and Al 2 O 3 as the matrix followed by spark plasma sintering. The nanocomposites have a higher elastic modulus and are able to endure higher plastic deformation than monolithic alumina. The microstructures of the dislocation, transgranular, and stepwise fracture surfaces are observed. Moreover, Al 2 O 3 -Cr 2 O 3 /Cr 3 C 2 nanocomposites have high hardness, fracture toughness, and facture strength due to strengthening by second phase Cr 3 C 2 particles and the solid solution of Al 2 O 3 -Cr 2 O 3 . © 2018 Elsevier Ltd. All rights reserved.