Abstract
Ultrasonic velocity measurements are used to determine the elastic properties of three different matrix alloys containing 6 percent alumina fibers and varying alumina particle volume fractions of 9, 13, and 17 percent. It is shown that the elastic module increase with the particle content and the composites have the highest elastic stiffness in the directions of the fiber plane. A model is developed to explain the observed elastic module of this type of composites. The agreement between measured and calculated elastic moduli is found to be good. The elastic moduli in two sets of extruded MMCs and one set of pressed MMCs are determined. These composites are reinforced with silicon carbide particles. Their elastic moduli as well as their elastic anisotropies are explained. (AIAA)