Amplitude and Phase Acoustic Microscopy and its Application to QNDE

Abstract

We have two amplitude and phase measuring acoustic microscopes, one at low frequency (3-10 MHz) which is used for measurements in metals and composites, and the other operating at frequencies of up to 200 MHz which is used for higher resolution measurements. The added dimension of having phase information allows us to use image processing for a variety of applications. We have demonstrated the following applications with these two microscopes: V(z) inversion for reflectance function calculations, depth determination for delaminations in composite materials, slowness curve measurements in anisotropic materials, image enhancement of subsurface defects, measurements of depth of trenches in aluminum samples (scaled problem of silicon trenches), and measurement of visco-elastic properties of thin surfactant films on a water surface.