|About this Abstract
||MS&T23: Materials Science & Technology
||Processing and Performance of Materials Using Microwaves, Electric and Magnetic Fields, Ultrasound, Lasers, and Mechanical Work – Rustum Roy Symposium
||High-speed Synchrotron X-ray Imaging of Microstructural Refinement Mechanisms During Ultrasonic Melt Processing in Metal Additive Manufacturing
||Lovejoy Mutswatiwa, Lauren Katch, Nathan Kizer, Tao Sun, Samuel J. Clark, Kamel Fezzaa, Christopher M. Kube
|On-Site Speaker (Planned)
Refined, equiaxed grain structure and improved mechanical properties are benefits of ultrasonic melt processing when applied during solidification in metal additive manufacturing (AM). However, the influence of ultrasonic vibrations on many of the solidification and microstructural refinement mechanisms in laser AM remain unknown. This presentation will focus on dynamics of laser-generated melt pools on an Al6061 sample sonicated at 20.2 kHz. The resulting melt pool behavior was captured using high-speed synchrotron X-ray imaging at the Advanced Photon Source. An X-ray image acquisition rate of 50 kHz allowed direct observation of cavitation bubbles in an opaque and viscous molten metal pool confined within microscale geometry. Furthermore, ultrasonic treatment reduced the solidification rate and caused pore migration toward the melt pool surface. These observations support the hypothesis that cavitation occurs when ultrasonic melt processing is used in laser AM and further facilitate continued investigation into the influence of cavitation on grain refinement.