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DTSTART;TZID="Pacific Time (US & Canada)":20260313T103000
DTEND;TZID="Pacific Time (US & Canada)":20260313T120000
SUMMARY:The School of Mechanical and Materials Engineering Seminar Series, “Materials in Extreme Applications: Compact Fusion” Presented by Dr. Sergey Tsurkan
LOCATION:Engineering Teaching Research Laboratory (ETRL), Pullman, WA
DESCRIPTION:Materials in Extreme Applications: Compact Fusion\n\nPresented by Dr. Sergey Tsurkan, Research Materials Scientist, Avalanche Energy\n\nAbstract:\n\nComplex concentrated alloys (CCA’s) have recently emerged as candidate materials for extreme environments such as those found within fusion reactors [1], [2], [3] and hypersonic systems [4]. A large area of CCAs are refractory high entropy alloys (RHEAs), these exhibit high melting points, stable mechanical properties and to an extent corrosion resistance. RHEAs can tackle two problems and would include the following: 1. Fusion reactors where irradiation damage is an issue 2. High temperature fusion or atmospheric environments where corrosion can take place. When it comes to point 1, normally the design parameters for creating such alloys include preventing intermetallic embrittling phases and optimizing nanostructure formations acting as defect sinks. For high heat flux environments, oxidation resistance and recrystallization effects are extremely important. The design process for these alloys consists of multiple down-selection tools in order to screen materials systems[1], [3], [6]. In its mission for sustainable fusion energy production, Avalanche energy seeks to develop and implement an integrated process for predicting novel refractory alloy systems for dual-use extreme environment applications. The validation process for this will consists of materials systems. The anticipated outcome of this project would directly aid in developing the operational and energy resilience. The resulting material systems will provide extreme environment resilience while utilizing an advanced manufacturing method using radioactively safe materials. These alloys will allow operation of critical infrastructure underwater or on national security critical technologies (e.g. nuclear reactors, aircraft).\n\n \n\nHigh performance novel materials are paramount to long lifetimes and performance in various infrastructure areas and national security. One such area is fusion energy which has emerged as the breakthrough technology in energy security and independence. RHEAs have emerged as an enabling technology for reactors that require irradiation and other extreme environment resilience. Current materials used in fusion reactors lack the longevity required to withstand fast 14.1 MeV neutrons found in D-T reactions which will be used in some of the first commercial units. The often-used W and W alloys have faced problems in oxidation environments and post-irradiation performance. For pure tungsten, the thermal conductivity of W degrades substantially after only 0.1 dpa of neutron damage [7],[8][Fig. 1]. Furthermore, W faces embrittlement issues at higher temperatures (< 1100 °C) [4]. When it comes to RHEAs, a multi-faceted approach must be taken to design and implement these novel alloys. Since the number of possibilities of alloy mixing is nearly infinite, there needs to be a robust down-selection process, this is where design parameters are optimized to narrow down the alloy element composition. The process can be initiated through calculating thermophysical values such as entropy and enthalpy of mixing, approximate melting point, atomic size difference, etc. Each has a specific purpose for alloy design, e.g. enthalpy of mixing is to be minimized if one wants to prevent short range order or phase separation [6], however trade-offs exist. Furthermore, to down-select systems quickly, high-throughput algorithms can be implemented to calculate entropy forming ability, enthalpic penalties to stability and phase separation processes.\n\nRecently, at Avalanche Energy in collaboration with partners, certain ternary alloys were synthesized as preliminary samples and showed promising microstructure and entropy stability behaviour. The samples consist of various ternary systems that have shown preliminary thermodynamic stability using thermophysical calculations, further characterization will give data about their performance and will therefore be fed back into the predictive model.  \n\n \n\nReferences\n\n[1]        O. El Atwani et al., “A quinary WTaCrVHf nanocrystalline refractory high-entropy alloy withholding extreme irradiation environments,” Nat Commun, vol. 14, no. 1, p. 2516, May 2023, doi: 10.1038/s41467-023-38000-y.\n\n[2]        J. W. Coenen, “Fusion Materials Development at Forschungszentrum Jülich,” Adv Eng Mater, vol. 22, no. 6, p. 1901376, Jun. 2020, doi: 10.1002/adem.201901376.\n\n[3]        O. El-Atwani et al., “Outstanding radiation resistance of tungsten-based high-entropy alloys,” Sci. Adv., vol. 5, no. 3, p. eaav2002, Mar. 2019, doi: 10.1126/sciadv.aav2002.\n\n[4]           Peters, A.B., Zhang, D., Chen, S. et al. Materials design for hypersonics. Nat Commun 15, 3328 (2024). https://doi.org/10.1038/s41467-024-46753-3\n\n[5]        B. Cantor, “Exploring Multicomponent Phase Space to Discover New Materials,” J. Phase Equilib. Diffus., Jul. 2024, doi: 10.1007/s11669-024-01131-w.\n\n[6]        D. B. Miracle and O. N. Senkov, “A critical review of high entropy alloys and related concepts,” Acta Materialia, vol. 122, pp. 448–511, Jan. 2017, doi: 10.1016/j.actamat.2016.08.081.\n\n[7]        L. Jochen, “High Heat Flux Performance of Plasma Facing Materials and Components Under Service Conditions in Future Fusion Reactors,” Fusion Science and Technology, vol. 53, no. 2T, pp. 278–287, Feb. 2008, doi: 10.13182/FST08-A1713.\n\n[8]        J. W. Coenen et al., “Materials for DEMO and reactor applications—boundary conditions and new concepts,” Phys. Scr., vol. T167, p. 014002, Feb. 2016, doi: 10.1088/0031-8949/2016/T167/014002.\n\n \n\nBiography:\n\nSergey Tsurkan is a Low Dimensional/Condensed Matter Physicist, whos' main efforts are currently directed at the development and characterization of novel materials in fusion environments and other extreme applications. He received his PhD in Low Dimensional/Condensed Matter Physics in 2020 from the Karlsruhe Institute of Technology, having done his Masters at Ruprecht Karl University of Heidelberg in Low Temperature Physics. Having spent one year as a Postdoctoral Scholar at University of Washington in the nano physics group, he continued his career with a clean hydrogen startup based in Bothell, WA. Following this Sergey joined Avalanche Energy to work in the Materials Science group. Sergey's background is in low temperature physics, thin film growth, low dimensional magnetism and metallic systems. In his free time, he enjoys training grappling and reading classical literature.
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