Lead P.I. - Dr. Jason R. Trelewicz

Plasma facing materials (PFMs) in future fusion reactors will be exposed to operating conditions involving high heat loads, rapidly evolving stresses, and aggressive particle and neutron fluxes.  Tungsten is presently the leading PFM due to its attractive high temperature properties; however, extended exposure to anticipated fusion conditions raises significant concerns about its microstructural stability, resilience against plasma-induced surface damage, and degradation of bulk properties due to neutron irradiation.  Guided by the hypothesis that the stability and performance under extreme conditions can be controlled through targeted doping of interfaces, this research topic seeks to advance tungsten alloys for the fusion environment with the following overarching objectives: (i) optimize dopant species for stabilization of tungsten against recrystallization and radiation induced property degradation, (ii) enable additive manufacturing (AM) of crack-free tungsten alloys for new divertor target geometries, and (iii) provide mechanistic insights and predict the performance envelope using atomistic simulations combined with finite element (FE) models.  Example results are shown above from nanoengineered tungsten alloys including (a) simulation of a W-Ti-Cr alloy, (b) bright-field TEM micrograph of a nanocrystalline W-Ti alloy, (c) sintering curves, and (d) stabilization against irradiation induced grain growth from in situ TEM experiments.  The scientific insights established through this project will markedly enhance the state of tungsten alloys for fusion applications, and in turn provide opportunities to validate their performance under relevant PFM conditions.