In this work, a novel (Hf_0.2Zr_0.2Ta_0.2Nb_0.2Ti_0.2)(N_0.5C_0.5) high‐entropy nitride‐carbide (HENC‐1) with multi‐cationic and ‐anionic sublattice structure was reported and their thermophysical and mechanical properties were studied for the first time. The results of the first‐principles calculations showed that HENC‐1 had the highest mixing entropy of 1.151R, which resulted in the lowest Gibbs free energy above 600 K among HENC‐1, (Hf_0.2Zr_0.2Ta_0.2Nb_0.2Ti_0.2)N high‐entropy nitrides (HEN‐1), and (Hf_0.2Zr_0.2Ta_0.2Nb_0.2Ti_0.2)C high‐entropy carbides (HEC‐1). In this case, HENC‐1 samples were successfully fabricated by hot‐pressing sintering technique at the lowest temperature (1773 K) among HENC‐1, HEN‐1 and HEC‐1 samples. The as‐fabricated HENC‐1 samples showed a single rock‐salt structure of metal nitride‐carbides and high compositional uniformity. Meanwhile, they exhibited high microhardness of 19.5 ± 0.3 GPa at an applied load of 9.8 N and nanohardness of 33.4 ± 0.5 GPa and simultaneously possessed a high bulk modulus of 258 GPa, Young's modulus of 429 GPa, shear modulus of 176 GPa, and elastic modulus of 572 ± 7 GPa. Their hardness and modulus are the highest among HENC‐1, HEN‐1 and HEC‐1 samples, which could be attributed to the presence of mass disorder and lattice distortion from the multi‐anionic sublattice structure and small grain in HENC‐1 samples. In addition, the thermal conductivity of HENC‐1 samples was significantly lower than the average value from the “rule of mixture” between HEC‐1 and HEN‐1 samples in the range of 300‐800 K, which was due to the presence of lattice distortion from the multi‐anionic sublattice structure in HENC‐1 samples.

中文翻译：

---

新型高熵金属氮化物的热物理和机械性能

在这项工作中，报道了一种具有多阳离子和阴离子亚晶格结构的新型（Hf _0.2 Zr _0.2 Ta _0.2 Nb _0.2 Ti _0.2）（N _0.5 C _0.5）高熵氮化碳（HENC-1）以及它们的热物理性质和首次研究了机械性能。第一性原理计算的结果表明，HENC-1的混合熵最高，为1.151R，导致HENC-1中600 K以上的Gibbs自由能最低，（Hf _0.2 Zr _0.2 Ta _0.2 Nb _0.2 Ti _0.2） N种高熵氮化物（HEN-1）和（Hf _0.2 Zr_0.2 Ta _0.2 Nb _0.2 Ti _0.2C高熵碳化物（HEC-1）。在这种情况下，HENC-1，HEN-1和HEC-1样品中的HENC-1样品通过最低温度（1773 K）的热压烧结技术成功制成。预制的HENC-1样品显示出金属氮化物的单一岩石盐结构，并且成分均匀性高。同时，它们在9.8 N的施加载荷下表现出19.5±0.3 GPa的高显微硬度，而纳米硬度为33.4±0.5 GPa，同时具有258 GPa的高体积模量，429 GPa的杨氏模量，176 GPa的剪切模量和弹性。模量为572±7 GPa。在HENC-1，HEN-1和HEC-1样品中，它们的硬度和模量最高，这可能归因于HENC-1样品中由于多阴离子亚晶格结构和小晶粒而引起的质量紊乱和晶格畸变。