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The transient thermal shock behaviors of W–ZrC/Sc 2 O 3 composites with different ZrC contents were evaluated using transient thermal shock test by electron and laser beams. The effects of different ZrC doping contents on the surface morphology and thermal shock resistance of W–ZrC/Sc 2 O 3 composites were then investigated. Similarity and difference between effects of electron and laser beam transient heat loading were also discussed in this study. Repeated heat loading resulted in thermal fatigue of the irradiated W–ZrC/Sc 2 O 3 samples by thermal stress, leading to the rough surface morphologies with cracks. After different transient thermal tests, significant surface roughening, cracks, surface melting, and droplet ejection occurred. W–2vol.%Sc 2 O 3 sample has superior thermal properties and greater resistance to surface modifications under transient thermal shock, and with the increasing ZrC content in W alloys, thermal shock resistance of W–Zr/Sc 2 O 3 sample tends to be unsatisfied.

In this study, we carried out the pre-irradiation of a dispersion-strengthened W-2wt.%Y2O3 alloy with good mechanical properties with high-energy Fe-ions instead of neutrons. The effect of this pre-irradiation on the D2 retention behavior of the alloy was investigated. A maximum of 1022 D/m2 was irradiated onto the samples using 5-keV D2 ions, and Fe pre-irradiation was carried out up to an ion fluence of 4 × 1018/m2 with 1 MeV energy. For comparison, commercial pure W was also studied. The Fe-ion pre-irradiation process increased the D2 retention in both pure W and the W–Y2O3 alloy. However, this D2 retention was independent of the pre-irradiation dose. In addition, the formation of He bubbles in the W–Y2O3 alloy caused by the irradiation at 1.8 × 1021 He/m2 and high temperatures of 773, 973, and 1173 K was also investigated. When the irradiation dose exceeded 1.5 × 1020 He/m2, visible He bubbles were formed, and He bubbles grew and void swelling increased with an increase in the irradiation dose. Compared to pure W, the W–Y2O3 alloy showed suppressed void swelling. This can be attributed to the dispersion of vacancies and He atoms due to the He irradiation.

W/steel composites are being developed for potential application in He gas-cooled divertors and plasma-facing components in fusion reactors. In this study, the dissimilar metal joints between W and Fe were fabricated at 950 °C via spark plasma sintering method with Ti foil (Ti–F) and Ti powder (Ti–P) as the interlayer under Ar atmosphere for 5 min at 57 MPa. Microscopic structures of the W/Fe diffusion joints with Ti–F and Ti–P were investigated and compared via field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Thermal cycling tests were employed to measure the thermal stability of different types of W/Ti/Fe samples. The hardness distribution across joining interfaces was also determined. After thermal cycling tests, a crack occurred along the W/Ti–P interface in the W/Ti–P/Fe samples, whereas the W/Ti–F/Fe samples were intact at the interfaces. Results revealed that Ti–F is more suitable as an interlayer than Ti–P, and the interfaces of the W/Ti–F/Fe samples have better thermal stability than those of the W/Ti–P/Fe ones.

W–Sc 2 O 3 composite powders (W, W–0.5 vol%Sc 2 O 3 , and W–2 vol%Sc 2 O 3 ) doped with highly uniform Sc 2 O 3 particles were successfully synthesized by mechanical alloying followed by hydrogen reduction with Sc 2 O 3 and WO 3 powders. The reduced powders were then consolidated by spark plasma sintering at 1700 °C to suppress grain growth during sintering. Field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy analyses, as well as tensile tests and thermal conductivity measurements, were used to characterize the samples. The results showed that the Sc 2 O 3 particles were uniformly distributed in the tungsten grains and grain boundaries. The W–2vol%Sc 2 O 3 composite possess the best relative density and Vickers micro-hardness up to 98.6% and 683.2 Hv, respectively. The Sc 2 O 3 particles significantly refine the grain size and increase the density of tungsten alloy. With increased Sc 2 O 3 content, the thermal conductivity decreased while tensile strength of the samples respectively increased at 700 and 800 °C.

Pure tungsten and W–3 wt.% Lu 2 O 3 samples were fabricated by spark plasma sintering at 1600 °C for 3 min from 4 h ball–milled powders. These samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectroscopy, Vickers microhardness, and thermal conductivity analyses. Results revealed that doped Lu 2 O 3 particles influenced the densifying and strengthening of W–3 wt.% Lu 2 O 3 composite compared with pure tungsten. The relative density and microhardness of pure tungsten were 93.49% and 446.4 Hv, and those for W–3 wt.% Lu 2 O 3 samples were 96.21% and 551.7 Hv, respectively.