Characterization of Metallic Glasses using Ultrasound Broadband Spectroscopy

Metallic glasses are a unique class of amorphous glassy materials whose mechanical properties lie between that of metals and ceramics. Owing to the random disorganized structure of metallic glasses, the characterization and determination of structure-property relationships is often difficult. Ultrasonic techniques have been previously used to characterize metallic glasses either by using the time-of-flight pulse-echo technique or Resonant Ultrasound Spectroscopy (RUS). The RUS methods are however limited to certain sample types and exhaustive preparation steps. This paper reports a ultrasound broadband spectroscopic (UBS) technique applied to the characterization of metallic glasses with minimal sample preparation, using a simple and portable arrangement. The ultrasound transducers employed are driven by very low input power (-15 dBm or less). A comparison of speed of sound measurements made using Pulse-echo and RUS techniques shows that the speed of sound data obtained by the UBS technique agrees to within +/- 0.5-6% relative to RUS, establishing the proposed UBS technique proves as a simple, non-destructive, and effective alternative method to enable rapid characterization of material properties.