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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >A high-entropy B-4(HfMo2TaTi) C and SiC ceramic composite
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A high-entropy B-4(HfMo2TaTi) C and SiC ceramic composite

机译：高熵B-4（HFMO2TATI）C和SIC陶瓷复合材料

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摘要

A multicomponent composite of refractory carbides, B4C, HfC, Mo2C, TaC, TiC and SiC, of rhombohedral, face-centered cubic (FCC) and hexagonal crystal structures is reported to form a single phase B-4(HfMo2TaTi) C ceramic with SiC. The independent diffusion of the metal and nonmetal atoms led to a unique hexagonal lattice structure of the B-4(HfMo2TaTi) C ceramic with alternating layers of metal atoms and C/B atoms. In addition, the classical differences in the crystal structures and lattice parameters among the utilized carbides were overcome. Electron microscopy, X-ray diffraction and calculations using density functional theory (DFT) confirmed the formation of a single phase B-4(HfMo2TaTi) C ceramic with a hexagonal close-packed (HCP) crystal structure. The DFT based crystal structure prediction suggests that the metal atoms of Hf, Mo, Ta and Ti are distributed on the (0001) plane in the HCP lattice, while the carbon/boron atoms form hexagonal 2D grids on the (0002) plane in the HCP unit cell. The nanoindentation of the high-entropy phase showed hardness values of 35 GPa compared to the theoretical hardness value estimated based on the rule of mixtures (23 GPa). The higher hardness was contributed by the solid solution strengthening effect in the multicomponent hexagonal structure. The addition of SiC as the secondary phase in the sintered material tailored the microstructure of the composite and offered oxidation resistance to the high-entropy ceramic composite at high temperatures.
机译：据报道，核心碳化物，B4C，HFC，MO2C，TAC，TiC和SiC，菱形，朝向立方（FCC）和六边形晶体结构的多组分复合物，形成单相B-4（HFMO2TATI）C陶瓷，SIC 。金属和非金质原子的独立扩散导致B-4（HFMO2TATI）C陶瓷的独特六边形晶格结构，具有金属原子和C / B原子的交替层。此外，克服了使用碳化物中的晶体结构和晶格参数的经典差异。电子显微镜，使用密度官能理论（DFT）的X射线衍射和计算证实了具有六边形紧密填充（HCP）晶体结构的单相B-4（HFMO2TATI）C陶瓷的形成。基于DFT的晶体结构预测表明，HF，Mo，Ta和Ti的金属原子在HCP晶格中的（0001）平面上分布，而碳/硼原子在（0002）平面上形成六边形2D网格。 HCP单位单元。与基于混合物规则（23GPa）估计的理论硬度值相比，高熵相的纳米率显示为35GPa的硬度值。较高的硬度是通过在多组分六方结构中的固溶强化作用导致的。作为烧结材料中的二次相的SiC加入SiC量身定制了复合材料的微观结构，并在高温下向高熵陶瓷复合材料提供了抗氧化性抗性。

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