研究材料宏观性能与微观结构之间的构效关系是材料科学研究的基本范式。镍基单晶高温合金用于航空飞机发动机高压涡轮叶片部分，其内部典型组织结构对合金性能的影响机制不容忽视。然而如何能够在大尺度下进行全面多尺度的分析，使微观结构表征具备宏观代表性，一直是材料表征面临的巨大挑战。为解决这一问题，本工作发展了多尺度材料研究手段，并成功将其应用于第二代与第四代镍基单晶高温合金组织物相研究中，探讨了高温合金内碳化物、拓扑密堆相（TCP相）以及γ/γ′相界面结构对合金蠕变性能的影响机制。 本论文首先发展了一种多尺度材料研究方法，以高通量扫描电子显微镜作为宏观与微观尺度的桥梁，结合机器学习与其他先进电子显微学表征手段，可实现材料物相宏观至原子尺度特性的协同测量。将发展的多尺度材料研究手段首次应用于含碳二代单晶内碳化物对合金影响机制的研究中，实现了合金高温低应力蠕变过程中碳化物种类、分布、组成元素、尺寸、形状以及与基体间取向关系等宏观至原子尺度特征的协同测定。多尺度研究结果表明，合金蠕变过程中存在大尺寸、与基体无良好共格关系的初生碳化物向小尺寸、与基体共格的次生碳化物演变的过程，这种转变可能对合金蠕变性能的提高起到不可忽视的作用。 随后将多尺度材料研究手段应用于四代单晶高温合金TCP相与界面强化的研究之中。电子叠层成像技术提高了以往合金TCP相研究的分辨率，辅助我们发现了一种σ相协同合金蠕变变形的新机制。σ相通过位错切割产生层错，此过程可以适当缓解σ相与γ′相之间的应力集中。最后，多尺度研究方法辅助揭示了四代单晶γ/γ′界面强化与失效机理。合金蠕变过程中形成完整的界面位错网，结合位错的不密实核心与元素富集起到界面强化的重要作用。加速蠕变阶段界面位错网络破坏，合金发生动态回复过程，引起合金快速变形失效。介观尺度的位错应力场分析揭示蠕变后期L-C位错的钉扎作用失效可能是界面位错网强化失效的主要原因之一。 利用多尺度材料研究方法，我们成功探讨了镍基单晶高温合金中具有宏观代表性的各类组织结构对合金性能的影响机制。该方法在镍基单晶高温合金中的成功应用证明了其在分析材料实际科学问题的可行性，本套多尺度材料研究方法有望广泛应用于研究多相材料结构-性能的构效关系上。

The linkage between microstructures and properties forms a fundamental paradigm in material science. As an important material for high-pressure turbine blades in aircraft engines, microstructures of nickel-based single crystal superalloys have significant impact on alloy performance. However, how to characterize the microstructure at appropriate length scale, which often requires information on the variation of nanoscale features over many length scales, is a key challenge. To overcome this issue, this work has developed a multiscale materials research method and successfully applied it in studying microstructures of second- and fourth-generation nickel-based single crystal superalloys. By using this method, our work explores the influence mechanisms of carbides, topologically close-packed (TCP) phases, and γ/γ′ interphase structure on the mechanism properties of superalloys during creep tests.This work first developed the multiscale materials research method by combining a single-beam high-throughput scanning electron microscope, machine learning and advanced electron microscopy techniques. This method enables the synergistic measurement of microstructure properties from macro- to atomic- scale. Thus, providing a technical foundation for multiscale studies on different phases in nickel-based single crystal superalloys.Firstly, we applied our developed method to characterize carbides evolution on a carbon containing second-generation nickel-based single crystal superalloys. This achieved large-area multiscale analysis of several different factors, such as the specific type, location, composition, size of carbides, and the relationship between carbides and matrix was achieved simultaneously. Macro- to atomic- scale analysis results indicate the transform from large size primary carbide with poor lattice compatibility to smaller size secondary carbides with coherent interface with matrix is in processing during creep. This carbide transformation during creep may have a positive effect on creep properties of the present superalloy.Then we applied this multiscale material research method on TCP studying in a fourth-generation nickel-based single crystal superalloys. Combining ptychography with ultra-high resolution, we directly resolve the atomic arrangements of an unusual stacking fault hidden in a σ phase precipitate in the superalloys. The experiment results indicate that the formation of this stacking faults formed by dislocations cutting into σ phase from γ′ phase, indicating σ phase deformed during high-temperature low-stress creep. The deformation of σ phase may help to relieve the dislocation pile-up and stress concentration at the σ/γ′ interfaces.Finally, we used this method to reveal the strengthening and failure mechanisms of γ/γ′ interfaces during high-temperature low-stress creep in fourth-generation nickel-based single crystal superalloys. In the early stages of creep, a complete interface dislocation network is formed at the γ/γ‘ interface through the proliferation and reaction of dislocations. The dislocation networks, combined with the non-dense core of dislocations and element enrichment play a significant role in interface strengthening. While, during the tertiary creep stage, the interface dislocation networks destructed gradually. In this time, a dynamic recovery process dominated by superdislocation cutting and the formation of sub-grain boundaries takes place in the superalloys, accelerating the creep deformation and leading to fracture. Besides, analysis of dislocation stress fields at the mesoscopic scale suggests that the failure due to the anchoring effect of L-C dislocations in the tertiary creep stage may be one of the main reasons for the failure of interface dislocation network strengthening.By employing the developed multiscale material research methods, we successfully investigated the impact mechanisms of typical microstructures on properties of nickel-based single crystal superalloys. Our combined results presented here verify the feasibility and accuracy of this technique in analyzing scientific issues of materials. We note that the ability can be expected to have widespread use for the analysis of structure-property relationships in multiphase materials.