Scanning Acoustic Microscopy—recent applications in materials science

Abstract

A convergent beam of ultrasonic waves at very high frequencies can be used in an acoustic microscope to achieve resolutions of the order of 1 μm at depths of up to 1 mm. One application of the acoustic microscope are welding tests (e.g. the Figure which shows an Si/Mo structure welded at 475°C).

Study of the elastic properties of sprayed SnO2 and SnS2 layers

“…Many authors [5,6] have described the principles of the acoustic signature and acoustic imaging techniques, provided by SAM. In this work, the SAM is composed of a focused acoustic with the operating principles previously described [7]. In our experiments, using an acoustic microscope working at 570 MHz in reflection mode and owing to the dispersion introduced by the characteristic dimension of the film (t < λ), the leaky generalized Lamb-mode velocities of each sample were precisely calculated from fast Fourier transform (FFT) spectra of V (z) curves.…”

“…Each mode in the acoustic signature appears in the Fourier spectrum as a peak whose maximum position gives us the period z, of the pseudo-oscillations in V (z). The mode velocity is then calculated by the formula [7] …”

Signature V(z) en microscopie acoustique : influence de la non-uniformité de l'illumination du capteur

“…L'optique géométrique n'est qu'un schéma équivalent qui ne peut être utilisé qu'une fois l'analyse des phénomènes correctement effectuée. L'utilisation de la phase du faisceau restant a permis dans certains cas d'améliorer d'un facteur 10 la précision de la mesure des vitesses de surface donnée par la signature V(z) classique [4].…”

Determination of mechanical properties of consolidated nanocrystalline iron–carbon alloys Fe–0.5%C and Fe–4.5%C by means of echography and acoustic microscopy

“…The velocity V R is deduced from the material acoustic signature obtained by interferometry with a high frequency (600 MHz) scanning acoustic microscope [7,8]. The acoustic signature V(z) curve of the consolidated ncFe-C alloys and the fast Fourier transform treated spectrum of V(z) were found similar to that of consolidated nc-Fe [3].…”