Dynamic elastic properties of SiC/2124AI metal matrix composite with SiC particle contents using resonant ultrasound spectroscopy

The dynamic elastic properties of metal matrix composites have been investigated using Resonant Ultrasound Spectroscopy(RUS). The composites used in this study consisted of 2124 aluminum alloy reinforced with different concentrations of SiC particles. RUS can determine the nine independent elastic stiffness(Cij) for the orthotropic symmetry on a small specimen simultaneously. Young's modulus, bulk modulus and shear modulus can be obtained from the measured stiffness. The calculated Young's moduli were compared with those from the tensile test along the direction of extrusion. The results show that the elastic stiffness and damping coefficient(Q'-'1) increase with particle content. The behavior of elastic stiffness indicates that the texture induced by the extrusion process changed from the transversely isotropic symmetry to the orthotropic symmetry as the reinforced particles increase. In addition, the fundamental normal modes of resonant frequencies in the same size of rectangular parallelepiped specimen tend to shift to higher frequencies as the volume fractions of reinforcements increase. This relationship could be used for determination of the volume fractions of reinforcements as a potential tool of nondestructive characterization.