Elastic constants of textured short-fiber composites

We studied the transversely isotropic elastic response of a series of textured short-fiber SiC/Al metal-matrix composites. By texture we mean the preferred orientation of the short fibers. We fully characterized the microstructure of the extruded SiC/Al short-fiber composites through a combination of mass-density measurements, optical and scanning electron microscopy, and neutron diffraction. We measured all components of the overall elastic-stiffness tensor of the composites using two methods: MHz-frequency pulse-echo ultrasonics and kHz-frequency acoustic-resonance spectroscopy, the latter being the first application of the method to short-fiber or particle-reinforced composites. We propose a relatively simple micromechanics model to predict the entire set of elastic constants, and give simple results for orientation distributions of practical significance. The predictions are in excellent agreement with measurements. Published by Elsevier Science Ltd