Description
A polycrystalline material is composed of discrete grains. The elastic properties of the grains are anisotropic and their crystallographic axes may be randomly or non-randomly oriented. In many industrial applications the ultrasonic inspection of such structures suffers from the anisotropy and/or the microscopic inhomogeneous arrangement of the grains on one side and from the scattering of the ultrasonic waves at the grain boundaries on the other side.