Investigation of the microstructure of cast iron by laser ultrasonic surface wave spectroscopy

We have used an all-laser surface wave ultrasonic method to investigate cas t iron samples with a variety of morphologies of included graphite precipit ation. The relation between ultrasonic attenuation and the microstructure o f cast iron is discussed. The frequency dependence of ultrasonic attenuatio n was obtained in a broad frequency band including the three characteristic regions of scattering. The scatterer size of the samples could be evaluate d from the measurement, and good agreement was found between the average sc atterer size estimated from our ultrasonic data and micrographic data. The demonstrated sensitivity of the ultrasonic propagation parameters to the mi crostructural properties of cast iron illustrates the strong potential of t his technique for non-destructive microstructural characterization of polyc rystalline materials. (C) 2001 Elsevier Science B.V. All rights reserved.