Recovering elastic constants of metal matrix composites via piezoelectric transducers and laser generated and detected ultrasonic waves

The ultrasonic evaluation of two kinds of metal matrix composites is carried out using two devices: an immersion bench with classical piezoelectric transducers and a contactless Nd:YAG laser point source/point receiver. The standard immersion device associated with an optimization process allows entire characterization of the two materials. Concerning their evaluation by the second method, the task is not a simple matter. Indeed, with this technique several modes are excited simultaneously which complicates the identification of their arrival times. So, the propagated modes and the nature of their corresponding velocities are discussed. However we present here only the first results for one of the two composites. The measurements carried out in the anisotropic principal plane are discussed for increasing angles of observation. We observe a good agreement between the measured longitudinal velocities by the laser device and those predicted by the immersion technique