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Highlights • Thermal shock behavior of samples was characterized after helium irradiation. • Combined helium irradiation and thermal shock has significant influence on crack propagation. • Observing fuzz was more likely to converge densely at the phase interface. • Y 2 O 3 doping can improve thermal shock resistance of the W-Y 2 O 3 composite. Abstract Tungsten can be the preferred plasma-facing material for nuclear fusion reaction. In this work, W-Y 2 O 3 composite powder was successfully fabricated through the wet chemical method, and bulk materials were obtained by rolling and high temperature annealing. W-2 vol% Y 2 O 3 was exposed to 80 eV helium ion irradiation with a flux of 1.5 × 1022 ions/(m2·s) at 1503–1553 K to assess its thermal shock resistance and helium ion irradiation damage behavior. The thermal shock behaviors of samples were studied under a laser beam. The energy densities of the laser thermal shock were 0.32, 0.48, and 0.64 GW/m2. W-Y 2 O 3 was compared with commercial pure tungsten. The hardness of pure tungsten and W-Y 2 O 3 before and after helium irradiation was measured by using a micro-hardness tester. The surface micrograph after helium ion irradiation and thermal shock was observed through scanning electron microscopy. Results show that W-Y 2 O 3 composite materials have better resistance to laser thermal shock than pure tungsten. [ABSTRACT FROM AUTHOR]

Abstract Tungsten is one of the most promising candidates for plasma-facing material for fusion. In this experiment, W–TiC–Y 2 O 3 composites were successfully prepared by the wet chemical method. The properties of the W–TiC–Y 2 O 3 composites were studied through field-emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction analysis, thermal conductivity, and transient laser thermal shock. During the sintering of the composite powder, TiC and Y 2 O 3 precipitations converted to Y-Ti-O precipitations. After transient laser thermal shock, the composites underwent melting, cracking, and resolidification, resulting in changes in surface morphology and internal structure of the composites. Graphical abstract Image 1 Highlights • W–TiC–Y 2 O 3 composites possessed excellent mechanical property and thermal shock resistance. • Y 2 TiO 5 , Y 2 TiO 6 , and Y 2 TiO 7 improved the mechanical properties of the material at high temperature. • The effect of different power density on material surface was analyzed. • The change of surface morphologies and internal structure due to transient thermal shock were discussed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Pure tungsten and tungsten alloys with 1, 2, and 3 wt.% Lu 2 O 3 were fabricated by mechanical alloying and spark plasma sintering at 1600 °C for 3 min. These samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive spectroscopy, Vickers microhardness, thermal conductivity analyses, thermal shock test, and deuterium retention. Results revealed that the microhardnesses of the samples have a similar trend with the relative density. With increased the doped Lu 2 O 3 content, the relative density and microhardness increased and the Lu 2 O 3 particles significantly increased the density and strengthened of tungsten alloy. With increased temperature from 300–1100 K, the thermal conductivity decreased with increased Lu 2 O 3 content. The doped Lu 2 O 3 particles revealed good enhancement effect in the thermal shock resistance and a good influence in the deuterium retention. [ABSTRACT FROM AUTHOR]

W-2%vol Y 2 O 3 composite material were prepared by wet-chemical and rolling methods. A comparative study was conducted with commercially pure tungsten. The laser thermal shock and the damage behavior of the material after helium ion irradiation were studied. The damage behavior was analyzed through X-ray diffractometry, field emission scanning electron microscopy, focused ion beam, field emission transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Results showed that W–Y 2 O 3 composite material have higher resistance to laser thermal shock than pure tungsten. Helium ion irradiation further illustrated that the cracking caused by laser thermal shock is dominated by intergranular cracks. In addition, tungsten matrix damage is associated with grain orientation deformation after the helium ion irradiation of pure tungsten and W–Y 2 O 3 composite material, and the grain orientation resistance to helium ion irradiation damage is higher than that to increasing grain boundary density. Several helium bubbles were found in the tungsten matrix, the fuzz structure, and the Y 2 O 3 particles, and all the helium bubbles were polyhedral rather than spherical. • W–Y 2 O 3 composite possess higher thermal shock resistance than pure tungsten. • Compared with increasing grain boundary density, grain orientation is more favorable to resist irradiation damage. • Helium bubbles were observed in the Y 2 O 3 particles. • The reported helium bubbles were polyhedral rather than spherical. [ABSTRACT FROM AUTHOR]