Ultrasonic Characterization of the Elastic Anisotropy in Aluminum-SiC and -Al2O3Metal Matrix Composites

Processing conditions such as those in the gravity cast and extruded metal-matrix composites (MMC) introduce a degree of anisotropy that must be taken into consideration in applications requiring high performance isotropic mechanical properties. The presence of anisotropy in composites can be viewed as the difference in the elastic modulus from one orientation to another, and the elastic constants can be determined from ultrasonic velocities and material densities. Contributions to anisotropy in MMC’s include the preferred alignment of crystalites in the matrix (texture) and the distribution and orientation of reinforcement particles. Models involving the effect of partial orientation and distribution of the reinforcement particles and texture were described by Sayers [1], and Spies and Salama [2] respectively. In this work, we use the former model to measure anisotropy in MMC’s