Stabilized Nanostructured and Laser Additively Manufactured Tungsten Alloys for Enhancing Divertor Armor Performance under Extremes

Jason Trelewicz

Stony Brook University

Tuesday, April 9, 2024

12:00pm

NW17-218 Hybrid

PSFC Seminars

Abstract: Continuous exposure of materials to fusion plasmas and the ensuing degradation in their properties has long been recognized as one of the most important challenges facing fusion energy. In the “Bringing Fusion to the U.S. Grid” National Academies Report, materials innovations were recognized as a top priority for producing net electricity in a fusion pilot plant by 2040. One significant materials challenge is the tungsten divertor armor, which is plagued by  high temperature stability due to recrystallization at approximately 1200°C, resilience against plasma-induced surface damage, and degradation of bulk properties due to the fusion neutron spectrum.  Additionally, tungsten will need to be fabricated into functional components with intricate geometric features, but the limited ductility of tungsten at room temperature makes it challenging to forge and machine parts more complex than sheets and rods. In this presentation, two enabling materials technologies are introduced for addressing the intrinsic limitations of tungsten.  First, grain boundary stabilized nanograined alloys are described where compositional complexities designed using computational thermodynamics modeling in the W-Ti-Cr system are used to produce predictively stable tungsten alloys.  Guided by alloy design maps, a series of ternary nanostructured tungsten alloys are synthesized through high energy ball milling and direct current sintering with thermal stability demonstrated at and above common recrystallization temperatures for tungsten.  Second, a CALPHAD-based alloy design strategy to fabricate laser additively manufactured (AM) tungsten materials free of process cracking and with improved fracture properties is presented. Results are contrasted with pure AM tungsten and discussed in the context of microstructural features and processing-related defects.  Collectively, these materials provide the basis for enhancing divertor armor performance to achieve the extreme conditions anticipated in pilot-scale Tokamak designs and represent a major step toward a net-zero carbon energy future.

Bio: Dr. Jason Trelewicz is an Associate Professor in the Department of Materials Science and Chemical Engineering at Stony Brook University with a joint appointment in the Institute for Advanced Computational Science.  His research explores the science of interface engineered materials for extreme environments using advanced characterization tools coupled with multi-scale modeling and simulation. Professor Trelewicz received his Ph.D. in Materials Science and Engineering from the Massachusetts Institute of Technology in 2008.  Prior to joining Stony Brook University, he spent four years as Research Director at MesoScribe Technologies, Inc.  Professor Trelewicz is a recipient of the DOE Early Career Award (2017) and NSF Faculty Early Career Award (2016).  His work on ceramic composite moderators was selected by the Journal of Nuclear Materials for the 2022 Best Paper Award, and he also co-authored a manuscript selected for the 2022 Journal of Asian Ceramic Societies Best Paper Award.  Professor Trelewicz was recognized by Long Island Business News Power 25 in Education as a Top Innovator in Energy Research and Stony Brook University as a 40 Under 40 Honoree.  He received the Fusen and Yijen Chen Prize for Innovative Research in 2018 and Young Leader Professional Development Award from the Minerals, Metals, and Materials Society (TMS) in 2015.  Professor Trelewicz serves as Chair of the TMS Nuclear Materials Committee, Review Editor for Frontiers in Nuclear Engineering, Board of Review Member and Key Reader for Metallurgical and Materials Transactions A, and Chair of the Tungsten Alloys Working Group for the International Energy Agency Fusion Materials Technology Collaboration Program.