The mechanical properties at the interfaces of TiCx/Ni3Al composites of four different C/Ti ratios were investigated using the nanoindentation technique. We find that the nanohardness and the elastic modulus from the phase TiCx, to the phase Ni3Al are a gradient distribution. As x increased from 0.6 to 0.9, the elastic modulus at the interface decreased. The interfacial nanohardness reached its peak value at x equal to 0.7. (C) 2002 Elsevier Science B.V. All rights reserved.