Determination of material parameters and texture of a polycrystalline aggregate from ultrasonic measurements

The propagation of ultrasonic waves in a polycrystalline aggregate is consi dered for a bulk sample with orthorhombic symmetry made of cubic crystals o f the highest symmetry. The probability density function of the crystallite orientation and the stiffness moduli of a single grain (crystallite) of th e polycrystalline aggregate are found from four ultrasonic velocities and t he rules of orthorhombic symmetry. Moreover, Jaynes' principle of maximum S hannon entropy and the averaging procedure proposed by Voigt are used. In t his way, it is shown that on the basis of the measurements of four respecti vely chosen ultrasonic velocities it is possible to find simultaneously the maximum-entropy distribution function of the crystallite orientation and t he crystallite stiffness moduli. (C) 1999 Elsevier Science Ltd. All rights reserved.