A high-entropy silicide: (Mo0.2Nb0.2Ta0.2Ti0.2W0.2)Si2
A high-entropy silicide: (Mo0.2Nb0.2Ta0.2Ti0.2W0.2)Si2
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DOI：
10.1016/j.jmat.2019.03.002
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发表时间：
2019-09-01
影响因子：
9.4
通讯作者：
Luo, Jian
中科院分区：
文献类型：
--
作者：
Gild, Joshua;Braun, Jeffrey;Luo, Jian
成功合成了高熵金属二硅化物(Mo0.2Nb0.2Ta0.2Ti0.2W0.2)Si-2。 X 射线衍射 (XRD)、能量色散 X 射线光谱 (EDX) 和电子背散射衍射 (EBSD) 共同显示了单一高熵硅化物相的形成。这种高熵(Mo0.2Nb0.2Ta0.2Ti0.2W0.2)Si-2具有ABC堆垛顺序的六方C40晶体结构和P6(2)22空间群。据我们所知，这一发现首次将已知的高熵材料家族从金属、氧化物、硼化物、碳化物和氮化物扩展到硅化物，并证明了一种新的非立方晶体结构（具有较低的对称性）可以制成高熵相。这种(Mo0.2Nb0.2Ta0.2Ti0.2W0.2)Si-2表现出16.7+/-1.9GPa的高纳米硬度和11.6+/-0.5GPa的维氏硬度。此外，它还具有6.9 +/- 1.1 W m(-1) K-1的低热导率，比广泛使用的四方晶系MoSi2的热导率低约一个数量级，与具有相同晶体结构的六方晶系NbSi2和TaSi2的报道值的1/3相似。 (C) 2019 中国硅酸盐学会。由 Elsevier B.V. 制作和主持
A high-entropy metal disilicide, (Mo0.2Nb0.2Ta0.2Ti0.2W0.2)Si-2, has been successfully synthesized. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and electron backscatter diffraction (EBSD) collectively show the formation of a single high-entropy silicide phase. This high-entropy (Mo0.2Nb0.2Ta0.2Ti0.2W0.2)Si-2 possesses a hexagonal C40 crystal structure with ABC stacking sequence and a space group of P6(2)22. This discovery expands the known families of high-entropy materials from metals, oxides, borides, carbides, and nitrides to a silicide, for the first time to our knowledge, as well as demonstrating that a new, non-cubic, crystal structure (with lower symmetry) can be made into high-entropy phase. This(Mo0.2Nb0.2Ta0.2Ti0.2W0.2)Si-2 exhibits high nanohardness of 16.7 +/- 1.9 GPa and Vickers hardness of 11.6 +/- 0.5 GPa. Moreover, it has a low thermal conductivity of 6.9 +/- 1.1 W m(-1) K-1, which is approximately one order of magnitude lower than that of the widely-used tetragonal MoSi2 and similar to 1/3 of those reported values for the hexagonal NbSi2 and TaSi2 with the same crystal structure. (C) 2019 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.