Hardness anisotropy and deformation-induced dislocations in (Hf-Ta-Zr-Nb)C high-entropy carbide grains of low-index facets were investigated using nanoindentation and transmission electron microscopy (TEM). The (Hf-Ta-Zr-Nb)C sample was prepared by a two-step spark plasma sintering (SPS) and nanoindentation was performed on grains mapped previously by electron backscatter diffraction. To investigate the deformation zones under the indents, thin lamellas were extracted from grains of {001}, {101} and {111} orientations using a focused ion beam (FIB) technique and were studied by TEM. Nanoindentation revealed that grains of {100} orientation exhibit about 7% lower hardness (~35 GPa) compared to the {110} and {111} facets (~38 GPa) while there was no anisotropy found for the indentation modulus. TEM analysis of the lamellas revealed heavily deformed zones under the indents with dislocations of $a/2〈1\overline{1}0〉$ type Burgers vector. TEM-based trace analysis of dislocations revealed the activation of the $〈110〉\left\{\overline{1}11\right\}$ and $〈110〉\left\{\overline{1}10\right\}$ slip systems in grains indented on the {001} and {101} facets, respectively. The hardness anisotropy of (Hf-Ta-Zr-Nb)C was attributed to the different operating slip systems, similar to that was reported for the component monocarbides in the literature.

使用纳米压痕和透射电子显微镜 (TEM) 研究了低指数面的 (Hf-Ta-Zr-Nb)C 高熵碳化物晶粒中的硬度各向异性和变形诱导位错。(Hf-Ta-Zr-Nb)C 样品是通过两步放电等离子烧结 (SPS) 制备的，并在先前通过电子背散射衍射绘制的晶粒上进行纳米压痕。为了研究压痕下的变形区，使用聚焦离子束 (FIB) 技术从 {001}、{101} 和 {111} 取向的晶粒中提取薄层，并通过 TEM 进行研究。纳米压痕表明，与 {110} 和 {111} 面 (~38 GPa) 相比，{100} 取向的晶粒硬度 (~35 GPa) 低约 7%，而压痕模量没有发现各向异性。$\mathrm{一种}/2〈1\overline{1}0〉$键入汉堡向量。基于 TEM 的位错痕量分析揭示了$〈110〉\left\{\overline{1}11\right\}$ 和 $〈110〉\left\{\overline{1}10\right\}$晶粒中的滑移系统分别在 {001} 和 {101} 面上缩进。(Hf-Ta-Zr-Nb)C 的硬度各向异性归因于不同的操作滑移系统，类似于文献中报道的组分一碳化物。