Recent developments in laser-ultrasonic technology have made it possible to remotely inspect large and complex aeronautic structures for structural integdty as well as gauge hot steel products on the production line. These developments based on laser and interferometer technology have also resulted in a powerful tool for characterizing materials and their microstructure. In fact the same features that make laser-ultrasonics attractive for the inspection of complex structures, such as relaxed requirements of the normalcy of the transducer, a broad frequency bandwidth, and large standoff distances make this technology unique and extremely useful for characterizing materials both in the laboratory and on the production line. Examples of recent developments and applications are presented. These relate to the measurement of microstructural features such as texture, grain size, degree of cold deformation in metals, solid4iquid4nterfaces. In particular, the real-time measurement of grain size during thermal processing is presented.
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