首页|Preliminary exploration of a WTaVTiCr high-entropy alloy as a plasma-facing material

Preliminary exploration of a WTaVTiCr high-entropy alloy as a plasma-facing material

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With great power comes great challenges. For nuclear fusion, the holy grail of energy, taming the flame of a miniature star in a solid container remains one of the most fundamental challenges. A tungsten armour for the solid container marks a temporary triumph-a solution adopted by the world's largest fusion experiment, ITER-but may be insufficient for future challenges. High-entropy alloys (HEAs), which are characteristic of a massive compositional space, may bring new solutions. Here, we explore their potential as plasma-facing materials (PFMs) with a prototype W_(57)Ta_(21)V_(11)Ti_8Cr_3 HEA that was designed by exploiting the natural-mixing tendency among low-activation refractory elements. Revealed by x-ray diffraction analysis and energy-dispersive x-ray spectroscopy, it predominantly consists of a single bcc-phase but with V, Ti, and Cr segregation to grain boundaries and at precipitates. Its yield strength improves ～60% at room temperature and oxidation rate reduces ~6 times at 1273 K, compared with conventionally used W. The Ti-V-Cr rich segregations and the formed CrTaO_4 compound contribute to the improved oxidation resistance. However, the Ti-V-Cr rich segregations, along with the decreasing valence-electron concentration of the matrix by the addition of Ta, V and Ti elements, considerably increase the deuterium retention of the W_(57)Ta_(21)V_(11)Ti_8Cr_3 HEA to ～675 multiples of recrystallized W. Moreover, its thermal conductivity decreases, being ～40% of W at 973 K. However, the maximum tolerable steady-state heat load is still ～84% of W because of its exceedingly high yield strength at elevated temperatures. Overall, despite being preliminary, we expect HEAs to play an important role in the development of advanced PFMs, for their disadvantages are likely to be compensated by their advantages or be overcome by composition optimization.

high-entropy alloysplasma-facing materialsnuclear fusion

Yu Li、Yuhan Sun、Long Cheng、Yue Yuan、Baohai Jia、Jiaqing He、Guang-Hong Lu、Guang-Nan Luo、Qiang Zhu

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Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, China, Shenzhen Key Laboratory for Additive Manufacturing of High-Performance Materials, Shenzhen, 518055, China

School of Physics, Beihang University, Beijing 100191, China

Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China

Institute of Plasma Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China, University of Science and Technology of China, Hefei 230026, China

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2022

10.1088/1741-4326/ac8fa5

Nuclear fusion

Nuclear fusion

SCI
ISSN：0029-5515
年,卷(期)：2022.62(12)
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