October 10, 2022 Seeing is Believing: Direct Observation of Metal Movement during Friction Stir Welding Written By: Caitlin Scott Departments: Mechanical Engineering Categories: Faculty|Research Mechanical Engineering Prof. Frank Pfefferkorn received an outstanding reception for his research group’s presentation “Predictive modeling of void formation and material flow with novel correlations between process forces and void morphology” at the International Symposium on Friction Stir Welding and Processing, held in Lüneburg, Germany on September 28-30, 2022. Pfefferkorn’s initial presentation of the work was so well received he was invited to augment the next day’s plenary talk and share his work with the entire conference. He was able to share direct observations of what is happening in the metal flow around the friction stir tool. The field had always hypothesized, suspected, and some models even showed the cavity formation and filling. However, all of those things were often written off by many because the fully consolidated weld retained little discernable evidence of what happened in the process. The in-situ imaging experiments were conducted in June 2022 at the Advanced Photon Source at Argonne National Lab. Pfefferkorn’s research team was awarded beamtime at APS to conduct high-energy high-speed x-ray imaging of friction stir welding. The 3-axis CNC mill from Pfefferkorn’s lab in the ME building was transported to and from APS for this purpose. Pfefferkorn and students Mo Ansari, Hemant Agiwal, Patrick Faue, and Daniel Franke, working closely with APS physicists Kamel Fezzaa and Samuel Clark, spent four days setting up the experiments and collecting data in early June 2022. This is just the “tip of the iceberg” in terms of what we still have to learn from the terrabyte of data that was collected and what in-situ high-speed high-energy X-ray imaging with the Advanced Photon Source can enable us to learn about metal manufacturing processes. Thank you to the National Science Foundation and grant CMMI-1826104 for their support. The first paper from this work is published in Manufacturing Letters. Agiwal, Hemant, Mohammad Ali Ansari, Daniel Franke, Patrick Faue, Samuel Clarke, Kamel Fezza, Shiva Rudraraju, Michael Zinn and Frank E. Pfefferkorn, “Material Flow Visualization during Friction Stir Welding using High-Speed X-Ray Imaging.” Manufacturing Letters. https://doi.org/10.1016/j.mfglet.2022.08.016 Featured image: Mo Ansari, Frank Pfefferkorn, and Hemant Agiwal in Pfefferkorn’s lab in the ME building before the CNC mill was moved to APS.