Mechanical & Materials Engineering, Department of


Date of this Version



AIP Conf. Proc. 1650, 926-934 (2015)


An elastic wave propagating in a metal loses a portion of its energy from scattering caused by acoustic impedance differences existing at the boundaries of anisotropic grains. Theoretical scattering models capture this phenomena by assuming the incoming wave is described by an average elastic moduli tensorC0ijkl (x) that is perturbed by a grain with elasticityCijkl (x ') where the scattering event occurs when x = x. Previous models have assumed that C0ijkl (x) is the Voigt average of the singlecrystal elastic moduli tensor. However, this assumption may be incorrect because the Voigt average overestimates the wave’s phase velocity. Thus, the use of alternate definitions of C0ijkl (x) to describe the incoming wave is posed. Voigt, Reuss, Hill, and self-consistent definitions of C0ijkl (x) are derived in the context of ultrasonic scattering models. The scattering-based models describing ultrasonic backscatter, attenuation, and diffusion are shown to be highly dependent on the definition of C0ijkl (x)