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Abstracts

“Degradation Mechanisms and Reusability of Refractory Metal Powders for Additive Manufacturing” by Mr. Michael Titus (WP23-3623) 

This project supports efforts to reuse and recycle strategic refractory metals and alloys for weapons systems and additive manufacturing. The project team is developing a scalable technology to recondition metal powder after multiple reuse cycles. Metal additive powder is reused during additive manufacturing by building components layer by layer, extracting components, and blending leftover powder with unused powder to refill equipment. In laser powder bed fusion, a high-power focused laser melts a 30 µm-thick layer of powder, ejecting particles and heating the powder bed to hundreds of degrees Celsius. These conditions negatively affect powder quality by enabling oxygen pickup, changing morphology and size, and affecting final component consolidation, chemistry, and properties. This presentation will show that oxygen pickup at the surface of reused powder is the most significant change, increasing oxygen and metal oxide concentration in as-built components. Despite these changes, overall mechanical performance remains largely unaffected after 14 cycles of powder reuse, suggesting some existing specifications may be relaxed. Recent efforts to remove oxygen from reused powder enable DoW reuse after several tens of cycles. 

“Additive Manufacturing and Reuse of Rhenium and Tungsten-Rhenium Alloy Powders” by Dr. Guru Dinda (WP23-3711) 

Additive manufacturing enables efficient material utilization and the recycling of expensive alloys, which supports waste minimization, cost reduction, and a reliable supply of strategic materials for future high-performance applications. This presentation will discuss the challenges and opportunities associated with additive manufacturing of tungsten (W), rhenium (Re), and  W-Re alloys. Additionally, the presentation will cover the properties of Re and W-Re alloy components produced by laser powder bed fusion using virgin and recycled powders. Findings underscore the promise of additive manufacturing and powder recycling for Re, demonstrating that high-performance, crack-free components can be achieved even with reused powders, while also emphasizing the need for continued innovation to overcome the challenges of producing crack-free W and W-Re alloy components. 

Speaker Biographies

Dr. Michael Titus is a tenured associate professor and technical director of the Purdue Heat Treating Consortium at the School of Materials Engineering at Purdue University in West Lafayette, Indiana. Mike’s expertise lies in non-ferrous metallurgy and includes fabrication, testing, characterization, and modeling, particularly in high-temperature deformation and oxidation. Mike is the recipient of the NSF CAREER award and many professional society awards. He has co-authored over 60 peer-reviewed publications. Mike earned his bachelor’s degree in engineering physics from The Ohio State University and his doctoral degree in materials from the University of California, Santa Barbara. 

Dr. Guru Dinda is a Senior Advisory Scientist at Savannah River National Laboratory (SRNL) in Aiken, South Carolina. Since 2020, Guru has led advanced research in metal additive manufacturing (AM) at SRNL, with a focus on accelerating the discovery and qualification of materials for use in extreme environments. Guru has developed laser and electron-beam AM processes for a diverse array of critical alloys, including tungsten, rhenium, tantalum, and their derivatives. His current research focuses on advancing innovative additive manufacturing and recycling technologies for critical materials and enabling the accelerated discovery of refractory high entropy alloys for mission-critical applications. Guru has authored more than 45 peer-reviewed publications. He earned his doctoral degree in materials science and engineering from the University of Saarland, Germany.