Mechanical Characterization of Fine-Grain Dispersion-Strengthened Tungsten as a Plasma Facing Material

Field-Assisted Sintering Technology (FAST) was used to produce fine-grained, dispersion-strengthened tungsten materials.  A series of mechanical property testing and microstructure studies were conducted to support novel tungsten development as a potential plasma facing material for the nuclear fusion reactor.  Specifically, high temperature tensile testing revealed likely oxygen contamination. Hardness testing showed that manufacturing conditions substantially altered hardness, with material 4355 slightly harder than ITER-grade tungsten, and 4353 substantially harder consequently, 4353, has smallest grain size of sub-micron value.  Electron Backscatter Diffraction (EBSD) analysis also showed that FAST produced substantially smaller grains than the hot-rolled ITER-grade tungsten material, with FAST processing conditions offering notable control over grain size.  Finally, thermal conductivity of the four types of materials all showed a decreasing trend as a function of temperature.  The ITER material has the highest thermal conductivity, and the 4353 and 4355 materials have the lowest, but similar thermal conductivity.  The 4138 material has thermal conductivity between these two groups. This study contributes significantly to the understanding of advanced tungsten-based materials designed for extreme operational conditions, providing insight into overcoming the inherent brittleness and instability seen in conventional tungsten materials. The use of FAST to produce fine-grained, dispersion-strengthened tungsten has demonstrated substantial technical effectiveness, improving mechanical and thermal performance under high-temperature and high-radiation conditions typical of fusion reactors. Furthermore, this research represents a critical step towards economically viable commercial fusion power, promising long-term operational reliability and enhanced safety.