Investigation of metal and ceramic-matrix composites moduli: Experiment and theory

The elastic behavior of metal and ceramic-matrix composites were characterized by ultrasonic techniques. While an immersion ultrasonic technique was used to measure the stiffness moduli of silicon carbide (SiC) particulate reinforced aluminium metal-matrix composites, a dry-coupling method was used to determine the elastic constants of woven Nicalon ™ fiber reinforced SiC ceramic-matrix composites. A unified micromechanics model was developed to predict the elastic moduli of these composites from the knowledge of their constituent elastic constants. The model quantitatively predicted the effects of microstructural characteristics, such as the reinforcement content and porosity in the material, on the elastic moduli of the composite systems studied. The predicted moduli were in good agreement with the experimental results for both the particulate reinforced metal-matrix composites and woven fiber reinforced ceramic-matrix composites.