AI 中文总结
本文结合实验与理论模拟，揭示了间隙碳显著加剧CrMnFeCoNi高熵合金中Cr原子周围的局部晶格畸变，为解释该合金的非单调扩散行为及碳诱导相变提供了关键依据。
AI 中文摘要
本文探究了多晶等原子面心立方CrMnFeCoNi高熵合金中与组分相关的局部晶格畸变，以及稀间隙碳对这些畸变的调控作用。多边扩展X射线吸收精细结构光谱结合反向蒙特卡洛分析表明，Cr组分经历的局部畸变最为显著，这一特性与长时间退火处理的温度（993 K或1373 K）以及名义碳含量（0至0.8 at.%）无关。研究发现，Cr原子周围的静态无序度会随碳合金化明显且单调增加，而Mn、Fe、Co、Ni则表现出较弱且非单调的变化趋势。碳诱导的晶格畸变会延伸至数个配位壳层，表明碳的存在对Cr吸收体周围的局部环境具有显著影响。第一性原理密度泛函理论及有限温度分子动力学模拟证实，相较于其他3d组元元素，碳对Cr周围局部晶格畸变的影响更大，这一结果基于此前的发现：碳优先占据富Cr的间隙位点。这些结果为阐明此前报道的碳掺杂CrMnFeCoNi合金中非单调扩散行为的原子起源提供了关键线索，对理解成分复杂体系中碳诱导的相变具有重要意义。
英文摘要
Here, we explore component-dependent local lattice distortions in polycrystalline, equiatomic, face-centered cubic CrMnFeCoNi high-entropy alloys and their modifications induced by dilute interstitial carbon. Multi-edge extended X-ray absorption fine structure spectroscopy combined with reverse Monte Carlo analysis reveals that the Cr component experiences the most substantial local distortions, independent of the temperature of prolonged annealing treatments (993 K or 1373 K) and the nominal carbon content (0 to 0.8 at.%). The static disorder around Cr atoms was found to increase markedly and monotonically upon carbon alloying, whereas Mn, Fe, Co, and Ni demonstrate weaker and non-monotonic tendencies. The carbon-induced lattice distortions extend over several coordination shells, indicating the pronounced effect of the carbon presence on the local environment around Cr absorbers. First-principles density functional theory and finite-temperature molecular dynamics simulations confirm the greater impact of carbon on the local lattice distortions around Cr than around the other $3d$ constituent elements, based on the previous finding that carbon preferentially occupies Cr-rich interstitial sites. These results provide decisive hints towards the atomistic origin of the non-monotonic diffusion behavior previously reported for carbon-doped CrMnFeCoNi alloys, and are noticeable for understanding the carbon-induced phase transitions in compositionally complex systems.
Journal refActa Mater. 319 (2026) 122664
DOI：10.1016/j.actamat.2026.122664
