Elastic properties of SiC, AIN, and their solid solutions and particulate composites

The elastic properties of SiC and AIN were determined at room temperature as a function of porosity by the resonant sphere technique. For an exponential relation, a zero porosity Young's modulus value (E0) of 437 GPa (63.4 X 10W psi) and an experimental constant (b) of 2.73 were found for SiC, and an E0 = 322 GPa (46.7 X 10W psi) and b = 2.44 for AIN. The elastic moduli of SiC-AIN solid solutions varied nearly linearly as a function of composition. The elastic moduli of SiC-AIN two-phase particulate composites were lower than those of the corresponding solid solutions and also lower than values calculated from composite theory, with the largest deviation at approx. =25% AIN and a gradual decrease to zero deviation at 100% AIN.