The influence of the free surface on the fracture of alumina particles in an Al–Al2O3 metal–matrix composite

The influence of the free surface on the load carried by elastic inclusions embedded in an elastic–plastic matrix was investigated by the finite element method. A 2D multi-particle model was developed based on the statistical evaluation of the microstructure of a commercial metal–matrix composite. The results of simulated tensile tests show that the average particle stresses are sensitive to the adopted boundary conditions. Inclusions near a free boundary carry in general smaller loads than the inclusions in the bulk. Damage predictions of the model are in good agreement with the experimental data obtained by X-ray microtomography.