Research and development of nanocrystalline W/W-based materials: novel preparation approaches, formation mechanisms, and unprecedented excellent properties

Tungsten(W)has become the most promising plasma-facing material(PFM)in fusion reactor,and W still faces performance degradation caused by low-temperature brittleness,low recrystallization temperature,neutron irradiation effects,and plasma irradiation effects.The modification of wW-based materials in terms of microstructure manipulation is needed,and such techniques to improve the performance of materials are the topics of hot research.Researchers have found that refining the grain can significantly improve the strength and the irradiation resistance of Ww-based materials.In this paper,novel approaches and technique routes,including the"bottom-up"powder metallurgy method and"top-down"severe plastic deformation method,are introduced to the fabrication of nanocrystalline WW-based materials.The formation mechanisms of nanocrystalline WW-based materials were revealed,and the nanostructure stabilization mechanisms were introduced.The mechanical properties of nanocrystalline WW-based materials were tested,and the irradiation behaviors and performances were studied.The mechanisms of their high mechanical properties and excellent irradiation-damage resistance were illustrated.This article may provide an experimental and theoretical basis for the design and development of high-performance novel nanocrystallineW/W-based materials.