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Scattering of ultrasonic waves in anisotropic polycrystalline.

Streuung von Ultraschallwellen in anisotropen polykristallinen Materialien
: Guo, C.B.; Goebbels, K.; Höller, P.

Acustica 59 (1985), S.112-120
ISSN: 0001-7884
ISSN: 1436-7947
Fraunhofer IZFP ()

It has been shown experimentally, that the scattered amplitudes of the ultrasonic waves in anisotropic polycrystalline metals decay with time in accordance with t high minus 3/4 e high minus Alpha sub a ct, when time t is not very short Alpha sub a = absorption coefficient, c = sound velocity). Scattered amplitudes observed at some distance from the sound-pulse source and their frequency spectra obtained experimentally behave in a way which cannot be explained by the current single scattering theory. A simplified diffusion theory was formulated. Theoretically calculated scattered amplitudes are in good agreement with the experimental ones. The "unusual" frequency spectra of scattered waves can be explained qualitatively in light of the diffusion theory. A new method of determining the sound absorption coefficient in polycrystalline metals can be derived from the diffusion theory.