Anisotropy measurements in metal alloys using a laser/electromagnetic acoustic transducer array system

Rayleigh waves have been used to measure anisotropy in metal alloys using a transient Rayleigh pulse and an eight-element electromagnetic acoustic transducer array. The array spacing determined sensor separation, so that velocity measurements were made independent of the source-to-detector distance. Elimination of this distance, which would normally lead to systematic errors, has resulted in a measurement system capable of measuring velocities in metal to an uncertainty of 0.1%. As an example, variations in the Rayleigh velocity have characterized the anisotropy in rolled bars of aluminum. © 2006 American Institute of Physics.