Microstructure and Properties of Sm2O3 Micro-Dispersed Tungsten-Based Alloy and Its Sintering Evolution

Tungsten (W) is regarded as the most promising plasma-facing material in thermonuclear fusion reactors due to its excellent properties, such as high strength, a high melting point, and a low sputtering rate. However, its low-temperature brittleness, recrystallization embrittlement, and irradiation embrittlement seriously limit the practical application of W. In this research, the properties of tungsten-based materials were improved by introducing second phases into W. Core–shell composite powders with W particles as core and Sm(OH)3thin films as shell were prepared by electroless plating, and sintered by spark plasma sintering (SPS) to obtain bulk. After sintering, the Sm(OH)3shell transformed into the Sm2O3phase with a different size, mainly distributed at W grain boundaries. The average size of W grains in the composite material was smaller than that of pure W sintered bulk due to the pinning of W grain boundaries by Sm2O3, while the porosity of the composite is reduced. Compared with pure W sintered bulk, the composites exhibited better mechanical properties and radiation resistance; although the thermal conductivity decreased somewhat, it still maintained a high level. With the increase in sintering temperature and pressure, the evolution of core–shell powders during the sintering process could be simplified into six stages, which occurred approximately in sequence.