Ultrasonic techniques for monitoring texture

One consequence of the elastic anisotropy of single crystals, the angular variation of ultrasonic wave speeds in a textured polycrystal, can be used as a measure of that texture. In cubic metals, it can be shown that three parameters can be obtained which characterize the texture, known as fourth order orientation distribution coefficients (ODC's). Examples of measurements of these parameters in iron, copper, and aluminum alloys and use of these data to predict formability parameters such as plastic strain ratio and degree of earing are presented. In hexagonal alloys, there are five ODC's accessible to ultrasonic measurement; two of second order and three of fourth order. The results of measurements of these in titanium and zirconium will be presented. In composites, such studies are complicated by interplay of the structurally and texturally induced anisotropies. The paper concludes with an example of studies of deformation induced changes in the texture of Cu in Cu-Nb and Cu-Ta filamentary composites