Materials Systems for the Future of Fusion Energy: On-Demand Poster Session
Sponsored by: TMS Structural Materials Division, TMS: Nuclear Materials Committee, TMS: Additive Manufacturing Committee, TMS: Computational Materials Science and Engineering Committee, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Jason Trelewicz, Stony Brook University; Kevin Field, University of Michigan; Takaaki Koyanagi, Oak Ridge National Laboratory; Yuanyuan Zhu, University Of Connecticut; Dalong Zhang, Pacific Northwest National Laboratory
Monday 8:00 AM
March 14, 2022
Room: Nuclear Materials
Location: On-Demand Poster Hall
Molecular Dynamics Simulations of Hydrogen and Nitrogen Implantation in Tungsten: Mary Alice Cusentino1; Mitchell Wood1; Aidan Thompson1; 1Sandia National Laboratories
Tungsten is currently the candidate material for the divertor component of future fusion reactors. The divertor will be subject to high particle fluxes of a variety of plasma species including both hydrogen and nitrogen. This results in a variety of microstructural changes including blister and tungsten-nitride formation. Molecular dynamics simulations can play a key role in both understanding physical processes leading to microstructural changes as well as providing information on hydrogen trapping and retention. However, accurate interatomic potentials are limited for these types of material interactions. In this work, we will discuss both the development of new machine learning interatomic potentials for studying hydrogen and nitrogen effects in tungsten and molecular dynamics simulations of hydrogen and nitrogen implantation in tungsten. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.
Modelling and Experimental Study of Yttrium Segregation in Smart Alloys as Plasma Facing Materials: Duc Nguyen-Manh1; Damian Sobieraj2; Jan Wrobel2; Mark Gilbert1; Joven Lim1; Ivan Povstugar3; Felix Klein3; Andrey Litnovsky3; 1UK Atomic Energy Authority; 2Warsaw University of Technology; 3Forschungszentrum Jülich GmbH
Self-passivating Metal Alloys with Reduced Thermo-oxidation (SMART) are under development as plasma-facing materials of the first wall in DEMO fusion device. The present SMART materials consist of tungsten, chromium as a passivating element and yttrium as the so-called active element. The phase stability and short-range order (SRO) of ternary alloys in W-Cr-Y systems have been investigated, using a combination of Density Functional Theory and Cluster Expansion methods with Monte-Carlo simulations. Our results showed that alloying yttrium with a concentration within 0.5-2.0 at.% into W-Cr alloys reveals positive SRO parameters for W-Y and Cr-Y pairs implying that yttrium tends to segregate from both W and Cr in the alloys. It is found that in the presence of yttrium, the predicted solid solution temperature is 400K lower than that of the binary 70W-30Cr. The role of yttrium in stabilizing the microstructure and improving the self-passivating capability is under experimental and modelling investigation.