A quantitative analysis of crack-interface interactions in alumina-based nanocomposites

Abstract

We extend the approach used earlier by He and Hutchinson (1989, Int. J. Solids Struct., 25, 1053) for the analysis of interface debonding in ceramics in order to treat the interactions of cracks in alumina-based nanocomposites with grain boundaries and ceramic nanoparticles. A criterion based on an analysis of the mechanical energy release rate and interfacial fracture energies is found to give good agreement with experimental observations of crack-particle interactions in Al₂O₃-SiC and Al₂O₃-TiN nanocomposites. In particular, it explains firstly why SiC particles located on grain boundaries inclined to the average direction of crack propagation are effective in deflecting intergranular cracks into the matrix grains and secondly why TiN particles are not effective in this way.