ASA 125th Meeting Ottawa 1993 May

1pPA1. Determination of texture coefficients in hexagonal polycrystalline aggregates with orthorhombic symmetry using ultrasonic waves propagating on one to three principal planes.

P. J. Kielczynski

A. Moreau

J. F. Bussiere

Industrial Mater. Inst., Natl. Res. Council of Canada, 75 De Mortagne Blvd., Boucherville, PQ J4B 6Y4, Canada

A method to characterize the texture of hexagonal polycrystalline aggregates with orthorhombic macroscopic symmetry is presented. Previous methods are extended to the analysis of waves propagating on three principal planes of the material. Five coefficients of the crystallographic orientation distribution function, W[sub 200], W[sub 220], W[sub 400], W[sub 420], and W[sub 440], are determined from angular variations of the phase velocity of the four ultrasonic modes considered: the bulk longitudinal waves, Rayleigh surface waves, the fundamental symmetric plate mode (in the long-wavelength limit), and shear-horizontal mode. Analytical expressions for the texture coefficients are found for an arbitrary number of principal planes. Measurements are reported for a Zr--2.5wt%Nb pressure tube, an alloy used in CANDU nuclear reactors. The angular variations of the phase velocity of leaky Rayleigh waves and leaky surface skimming compressional waves are measured with a line-focus acoustic microscope. The results agreed with neutron scattering measurements.