In this study, we reveal the impact of the addition of TiC in the IN718 superalloys at both atomic and micron scales through density functional theory (DFT), molecular dynamics (MD), and experimental analysis. From the micro scales, the addition of TiC can effectively mitigate the segregation behavior of Nb and Mo atoms, promote heterogeneous nucleation, reduce grain size, and thus improve mechanical properties. From the atomic scales, the effect of alloying elements (Fe, Cr, Mo, Nb, Co) on the stability of the TiC/γ-Ni interface was investigated through first principles. Co-doping interface was more stable than other interfaces by MD calculations, followed by Cr and Fe-doping models. The heat of segregation results inferred that TiC can effectively mitigate the segregation behavior of Nb and Mo atoms in the TiC/γ-Ni interface, it is mutually verified with the experimental results. Furthermore, the interface energy values theoretically illustrated that TiC particles could promote the heterogeneous nucleation of γ-Ni, this behavior of TiC particles was verified by experiment results. This investigation results provide reference information in the study of ceramic particle reinforced alloys at atomic and micron scales.

中文翻译：

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添加 TiC 对激光直接金属沉积制备的 IN718 界面稳定性、微观结构和机械性能的影响：实验、DFT 和 MD 研究相结合

在这项研究中，我们通过密度泛函理论 (DFT)、分子动力学 (MD) 和实验分析揭示了 IN718 高温合金中添加 TiC 在原子和微米尺度上的影响。从微观尺度来看，TiC的添加可以有效缓解Nb和Mo原子的偏析行为，促进异质形核，减小晶粒尺寸，从而提高力学性能。从原子尺度出发，通过第一性原理研究了合金元素（Fe、Cr、Mo、Nb、Co）对TiC/γ-Ni界面稳定性的影响。通过MD计算，共掺杂界面比其他界面更稳定，其次是Cr和Fe掺杂模型。偏析热结果推断TiC可以有效缓解TiC/γ-Ni界面中Nb和Mo原子的偏析行为，与实验结果相互验证。此外，界面能值从理论上说明了TiC颗粒可以促进γ-Ni的异相成核，实验结果也验证了TiC颗粒的这种行为。该研究结果为原子和微米尺度陶瓷颗粒增强合金的研究提供了参考信息。