Laser-ultrasonic attenuation and absorption measurements in metals

Abstract

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Laser-Ultrasonic attenuation and absorption measurements in metals NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=18968550&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=18968550&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCFor the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous. ABSTRACT. The attenuation of an acoustic wavefront in metals comes from scattering caused by grain anisotropy and random grain orientation and from absorption caused by mechanisms such as dislocation and magnetic domain motion. In this paper laser ultrasonics, with its non-contact and broadband characteristics, is used for measuring and separating these two attenuation contributions as a function of frequency. Results obtained from the well-known pulse-echo method and reverberation technique are presented first. Then, a more recent approach using a time-frequency analysis with zerogroup velocity (ZGV) resonances is considered. It is shown that the attenuation with scattering and absorption components is obtained by fitting the temporal decay of the resonances of the coherent field, and that only the absorption component is obtained from the temporal decay of the diffuse field between resonances. LASER-ULTRASONIC ATTENUATION AND ABSORPTION MEASUREMENTS IN METALS