Development of Cold Spray Additive Manufacturing for Tungsten-Based Plasma-Facing Components

Dr. Grant Crawford¹, Professor

Co-PI(s): Dr. Eric Lang², Dr. Nathan Madden¹, Dr. Forest Thompson¹, Dr. Bharat Jasthi¹

1: South Dakota School of Mines and Technology, Rapid City, SD 57701

2: The University of New Mexico, Albuquerque, NM 87131

The objective of the project is to investigate and develop cold spray additive manufacturing of tungsten-based materials for plasma-facing component manufacturing and repair. South Dakota School of Mines and Technology (SDM), along with their partners at the University of New Mexico (UNM), will define the multi-dimensional relationships between cold spray processing conditions, microstructural characteristics, and helium-induced degradation behavior of tungsten-based materials produced by cold spray technology. SDM, a non-R1 emerging research institution, is uniquely positioned to lead this research effort due to the combination of state-of-the-art facilities with extensive expertise in additive manufacturing technology. This research program will not only mark the beginning of fusion energy research at SDM, but will also foster a new collaboration with UNM, a Hispanic Serving Institution (HSI) and an emerging leader in fusion energy research. Furthermore, it will provide education and training opportunities for undergraduate and graduate researchers, representing the next generation of fusion energy scientists. This research will systematically study the cold spray processing of tungsten-based materials and establish the response of their microstructures to fusion-irradiation conditions. Cold spray is a solid-state additive manufacturing technique that produces unique microstructural features and can be used for in-situ manufacturing and repair. This work will build upon the cold spray deposition expertise previously developed at SDM by processing refractory materials suitable for use as plasma-facing materials (PFMs) for fusion reactors, which are relatively unstudied in the field of cold spray technology. Additionally, this work will establish connections between SDM and experts in the fusion community by partnering with UNM. Four primary research tasks will be carried out. Task 1 will focus on the discovery of processing-microstructure relationships in tungsten-based cold spray. The cold spray process generates numerous tunable microstructures that are beneficial for PFMs. Four tungsten-based PFMs with increasing structural complexity will be investigated: (i) pure tungsten; (ii) zirconium carbide doped tungsten; (iii) tungsten-tantalum binary alloys, and (iv) a combination of (ii) and (iii). Task 2 will focus on measuring cold spray coating mechanical properties, including adhesion strength, hardness, and cohesive strength, which will affect PFM functionality. In Task 3, researchers will perform ion irradiation experiments and characterize the resulting microstructure and mechanical properties. Cold spray microstructures are expected to alter and mitigate structural changes induced in PFMs by low energy, high fluence helium ion irradiation. Finally, Task 4 will focus on the development of the low-temperature and solid-state cold spray process technology for the repair of tungsten-based plasma facing materials. The project will enable the design of tungsten-based alloys and composites with inherent resistance to irradiation-induced damage. It is hypothesized that: (i) compared to wrought tungsten, microstructurally-optimized tungsten-based cold spray coatings will exhibit less irradiation-induced nanostructuring and bubble formation, (ii) in-situ peening during the cold spray process will develop microstructures that limit the formation of helium bubbles, (iii) cold spray coatings will have less radiation-induced degradation in micromechanical properties (e.g., irradiation hardening) when compared to wrought tungsten, and (iv) plasma-facing components repaired by cold spray will retain their initial PFMs performance. Ultimately, successful completion of this research will advance the fusion community’s manufacturing toolbox by demonstrating the feasibility of using cold spray in fusion-relevant irradiation conditions.

This research was selected for funding by the Office of Science

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