Non-destructive evaluation of bulk metallic glass components using resonance ultrasound spectroscopy

Bulk Metallic Glasses (BMGs) are becoming prevalent as specialty components in aerospace, energy, and medical technologies, and hold long-term potential as consumer good components. When manufacturing BMG components by solidification and thermoplastic forming, however, even small deviations from optimal processing conditions can alter the structural glass state, promote crystallization, and introduce geometric flaws. Established techniques to evaluate the integrity of BMG components are often expensive, time-consuming, and destructive in nature. In this study, we employ Resonance Ultrasound Spectroscopy (RUS) as an inexpensive, fast, and nondestructive alternative to accurately measure the elastic properties of BMG components and thus estimate their fictive temperature. Further, RUS can detect crystallinity and geometric flaws. These capabilities are demonstrated even for complex component geometries, based on a BMG planet gear here.