Influence of crack path on crack resistance of brittle matrix composites

Studies on particulate reinforced ceramic composites, mainly glass/Al2O3, have shown pronounced crack path variations with variations in microstructure and loading rate. The variations in path strongly influenced the crack resistance of the composite. For composites where the particles have lower thermal expansion and higher Young's modulus than the matrix, greater crack-particle interactions lead to a decrease in crack resistance. Composites where the particles have higher thermal expansion and higher Young's modulus than the matrix showed increasing crack resistance with increasing crack- particle interaction. A theoretical model was developed to explain the results.