Classical and novel methods in scanning acoustic microscopy for NDT-applications

With commercial scanning acoustic microscopes the volume of a specimen can be examined by ultrasonic waves. These waves are excited by a piezoelectric transducer and are usually focused to a specific depth. The reflected waves are measured and analysed. By lateral scanning a sectional image can be produced. Producing images of a bigger volume in this way is very inefficient and sometimes even impossible. In this article a tomography technique is introduced that realises capturing of the entire volume by only one two-dimensional scan. All discoverable flaws in this volume, e.g. pores, inclusions as well as tilted cracks can be displayed with true size and position in the volume. © Carl Hanser Verlag.