Modeling the relationship between microstructural features and the strength of WC-Co composites

A two-dimensional finite element method (FEM) was used to predict the stress-strain distributions and the fracture strengths of WC-Co composites with carbide grain sizes from 1.4 to 5.3 μm and carbide volume fractions from 0.7 to 0.9. Stress-strain distributions were calculated in plane sections of microstructures mapped by orientation imaging microscopy. An effective fracture energy was set so that the measured strength of each material was reproduced by the simulation. This model was then used to simulate the properties of hypothetical microstructures to investigate the influence of independent variations in microstructural characteristics on strength. The results indicate that composites with minimum contiguity, containing highly angular, and equiaxed carbide grains with a narrow size distribution should have the maximum strength. Of these parameters, contiguity is the most influential.