Acta Materialia最新文献_第5页

Enhanced reliability of Cu-Sn bonding through the microstructure evolution of nanotwinned copper 通过纳米缠绕铜的微结构演变提高铜锡键合的可靠性

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-30 DOI: 10.1016/j.actamat.2024.120524

Xinyu Jin , Huahan Li , Yingying Sun , Zhiqin Chen , Peixin Chen , Hongwei Su , Ming Li , Yunwen Wu

Kirkendall voids are detrimental to the Cu-Sn bonding interface, causing the failure of the high-density package. Herein, the perpendicularly aligned nanotwinned Cu (p-ntCu) and the horizontally aligned nanotwinned Cu (h-ntCu) are prepared by controlling the electrodeposition procedure. The p-ntCu shows advantages both in fast-bonding process and in void suppression through the in-situ microstructure evolution. Compared with h-ntCu, the abundant perpendicularly aligned twin boundaries in p-ntCu provide fast interdiffusion paths to build a bonding interface. In the bonding process, p-ntCu grows to ultra-large-grained Cu with an average grain size of 6.68 μm. The reduced density of normal grain boundaries in p-ntCu lowers the Cu diffusion rate and contributes to more balanced interdiffusion at the bonding interface, which is confirmed by molecular dynamics simulation and kinetic calculations of intermetallic compound (IMC) growth. In addition, the low impurity content in p-ntCu further reduces the diffusion flux imbalance and limits the nucleation of Kirkendall vacancies. Consequently, the p-ntCu/Sn interface keeps void-free during 150 °C long-term thermal aging due to the synergistic effect of reduced grain-boundary diffusion and lower impurity content, which will be beneficial for achieving high-reliability Cu-Sn bonding.

Kirkendall 空隙不利于铜锡结合界面，导致高密度封装失效。在此，通过控制电沉积程序制备了垂直排列的纳米铜（p-ntCu）和水平排列的纳米铜（h-ntCu）。p-ntCu 在快速键合过程和通过原位微结构演化抑制空隙方面都具有优势。与 h-ntCu 相比，p-ntCu 中大量垂直排列的孪晶边界为建立键合界面提供了快速的相互扩散路径。在键合过程中，p-ntCu 长成平均晶粒尺寸为 6.68 μm 的超大晶粒铜。p-ntCu 中正常晶界密度的降低降低了铜的扩散速率，并有助于在键合界面形成更平衡的相互扩散，这一点已通过金属间化合物（IMC）生长的分子动力学模拟和动力学计算得到证实。此外，p-ntCu 中的低杂质含量进一步降低了扩散通量的不平衡，并限制了 Kirkendall 空位的成核。因此，在减少晶界扩散和降低杂质含量的协同作用下，p-ntCu/Sn 界面在 150 °C 长期热老化过程中保持无空隙，这将有利于实现高可靠性的铜锡结合。

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引用次数: 0

Magnetic field controlled surface localization of ferromagnetic resonance modes in 3D nanostructures 三维纳米结构中铁磁共振模式的磁场控制表面定位

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-29 DOI: 10.1016/j.actamat.2024.120499

Mateusz Gołębiewski , Krzysztof Szulc , Maciej Krawczyk

By extending the current understanding and use of magnonics beyond conventional planar systems, we demonstrate the surface localization of ferromagnetic resonance (FMR) modes through the design of complex three-dimensional nanostructures. Using micromagnetic simulations, we systematically investigate woodpile-like scaffolds and gyroids — periodic chiral entities characterized by their triple junctions. The study highlights the critical role of demagnetizing fields and exchange energy in determining the FMR responses of 3D nanosystems, especially the strongly asymmetric distribution of the spin-wave mode over the system’s height. Importantly, the top–bottom dynamic switching of the surface mode localization across the structures in response to changes in magnetic field orientation provides a new method for controlling magnetization dynamics. The results demonstrate the critical role of the geometric features in dictating the dynamic magnetic behavior of three-dimensional nanostructures, paving the way for both experimental exploration and practical advances in 3D magnonics.

我们通过设计复杂的三维纳米结构，展示了铁磁共振（FMR）模式的表面定位，从而将目前对磁学的理解和应用扩展到传统的平面系统之外。利用微磁模拟，我们系统地研究了木桩状支架和陀螺--以三重连接为特征的周期性手性实体。研究强调了去磁场和交换能在决定三维纳米系统的调频响应中的关键作用，尤其是自旋波模式在系统高度上的强烈非对称分布。重要的是，随着磁场方向的变化，整个结构的表面模式定位会从上到下发生动态切换，这为控制磁化动态提供了一种新方法。这些结果证明了几何特征在决定三维纳米结构动态磁行为中的关键作用，为三维磁学的实验探索和实际进展铺平了道路。

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引用次数: 0

On identifying dynamic length scales in crystal plasticity 关于确定晶体塑性的动态长度尺度

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-29 DOI: 10.1016/j.actamat.2024.120506

Dénes Berta , David Kurunczi-Papp , Lasse Laurson , Péter Dusán Ispánovity

Materials are often heterogeneous at various length scales, with variations in grain structure, defects, and composition which has a strong influence on the emergent macroscopic plastic behavior. In particular, heterogeneities lead to fluctuations in the plastic response in the form of jerky flow and ubiquitous strain bursts. One of the crucial aspects of plasticity modeling is scale bridging: In order to deliver physically correct crystal plasticity models, one needs to determine relevant microstructural length scales. In this paper we advance the idea that continuum descriptions of dislocation mediated plasticity cannot neglect dynamic correlations related to the avalanche behavior. We present an extensive weakest link analysis of crystal plasticity by means of three-dimensional discrete dislocation dynamics simulations with and without spherical precipitates. We investigate strain bursts and related length scales and conclude that while sufficiently strong obstacles to dislocation motion tend to confine the dislocation avalanches within well-defined sub-volumes, in pure dislocation systems the avalanches may span the system, implying that the dynamic length scale is, in fact, the size of the entire sample. Consequences of this finding on continuum modeling are thoroughly discussed.

材料在不同的长度尺度上通常是异质的，晶粒结构、缺陷和成分的变化对宏观塑性行为有很大影响。特别是，异质性会导致塑性响应的波动，表现为生涩的流动和无处不在的应变爆发。塑性建模的一个重要方面是尺度桥接：为了建立物理上正确的晶体塑性模型，我们需要确定相关的微结构长度尺度。在本文中，我们提出了一个观点：对位错介导塑性的连续描述不能忽略与雪崩行为相关的动态关联。我们通过有无球形析出物的三维离散位错动力学模拟，对晶体塑性进行了广泛的最薄弱环节分析。我们对应变爆发和相关长度尺度进行了研究，并得出结论：虽然足够强的位错运动障碍往往会将位错雪崩限制在定义明确的子体积内，但在纯位错系统中，雪崩可能会跨越整个系统，这意味着动态长度尺度实际上是整个样品的大小。我们深入讨论了这一发现对连续模型的影响。

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引用次数: 0

Step flow mechanism in dissolutive wetting Cu/Ni systems 溶解润湿铜/镍体系中的阶跃流动机制

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-28 DOI: 10.1016/j.actamat.2024.120519

Youqing Sun , Zhongfu Cheng , K. Vijay Reddy , Diqiu He , Ensieh Yousefi , Miral Verma , Nele Moelans , Muxing Guo , David Seveno

The Cu-Ni system is a typical dissolutive system due to its mutual dissolution across a wide range of temperatures and compositions. We characterized the effects of Ni dissolution on the wetting behavior of liquid Cu by combining high-temperature wetting experiments, in-situ observation of spreading and solidification, microstructure analysis of the quenched droplets, and computational fluid dynamic (CFD) simulations. In the very early moment, at 1100 °C, when the Cu droplet is brought in contact with the Ni substrate, it oscillates due to capillarity and is dampened by inertial effects, while the significant Ni dissolution at 1150 °C largely reduced the initial oscillations. Later, a peculiar spreading behavior is observed and we propose to describe it through a 4-step mechanism: pinning of the contact line by a newly formed solid solution layer at the interface acting as a physical barrier, driving of liquid towards the solidified edge due to a Ni-concentration induced Marangoni flow, forming of a precursor film ahead of the solidified edge caused by the strong Cu-Ni interactions and Marangoni flow, and finally depinning due to overflow as a result of liquid accumulation at the solidified edge. The formation of a solid solution layer is confirmed by in-situ observation and quenching. The Ni-concentration induced Marangoni flow is characterized experimentally and further investigated by CFD simulations. The proposed step flow mechanism can be potentially relevant to other dissolutive wetting systems (e.g. Bi/Sn, Ag/Cu and Cu/Fe systems), which are crucial for high-temperature processing techniques.

铜-镍体系是一个典型的溶解体系，因为它在很宽的温度和成分范围内相互溶解。我们结合高温润湿实验、原位观察扩散和凝固、淬火液滴的微观结构分析以及计算流体动力学（CFD）模拟，研究了镍溶解对液态铜润湿行为的影响。在 1100 ℃ 时，铜液滴与镍基底接触的初期，由于毛细管效应，液滴会发生振荡，并受到惯性效应的抑制，而 1150 ℃ 时镍的大量溶解在很大程度上减少了初期的振荡。后来，我们观察到了一种奇特的扩散行为，并建议通过以下四步机制来描述这种行为：在界面上新形成的固溶体层作为物理屏障将接触线固定；由于镍浓度引起的马兰戈尼流，液体被驱向凝固边缘；由于强烈的铜镍相互作用和马兰戈尼流，在凝固边缘前形成了前驱膜；最后，由于凝固边缘的液体积聚导致溢流，从而造成去薄化。现场观察和淬火证实了固溶层的形成。镍浓度诱导的马兰戈尼流具有实验特征，并通过 CFD 模拟进行了进一步研究。所提出的阶梯流动机制可能与其他溶解润湿体系（如 Bi/Sn、Ag/Cu 和 Cu/Fe 体系）相关，这些体系对于高温加工技术至关重要。

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引用次数: 0

Shrinkage and deformation of material extrusion 3D printed parts during sintering: Numerical simulation and experimental validation 材料挤压 3D 打印部件在烧结过程中的收缩和变形：数值模拟和实验验证

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-28 DOI: 10.1016/j.actamat.2024.120518

Sri Bharani Ghantasala , Gurminder Singh , Jean-Michel Missiaen , Didier Bouvard

Material extrusion 3D printing (ME3DP) combined with sintering is a low-cost additive manufacturing technique for fabricating components of difficult-to-print metals, such as copper, aluminum, and ceramics. However, the sintering process includes complex material science, such as volumetric shrinkage and free structural bending, to identify the relative density and deformation of a 3D printed sample. The prediction of the relative density and deformations during the sintering process provides information to the design engineer to optimize the design of the CAD model before sintering. In this study, a phenomenological model based on constitutive equations was developed to predict the density and structural deformation during the sintering process of pure copper components fabricated by ME3DP using metal injection molding feedstock. The densification rate was determined using shrinkage estimation with an isothermal stairway heating cycle in a vertical dilatometer. Furthermore, different sets of experiments were performed with a load on the probe with long isothermal heating cycles at 850, 900, 950, 1000, and 1050 °C in a vertical dilatometer to estimate the axial viscosity of the copper. The constitutive equations were solved using the solid mechanics module with user-defined creep in COMSOL Multiphysics by considering isotropic assumptions. Two types of geometries, cube and overhanging I section, were used to predict shrinkage and deformation during the sintering process. The developed model successfully predicted the relative density based on shrinkage and structural deformation owing to gravity during the sintering process.

材料挤压三维打印（ME3DP）与烧结相结合是一种低成本的增材制造技术，可用于制造铜、铝和陶瓷等难以打印的金属部件。然而，烧结过程包括复杂的材料科学，如体积收缩和自由结构弯曲，以确定 3D 打印样品的相对密度和变形。预测烧结过程中的相对密度和变形为设计工程师在烧结前优化 CAD 模型设计提供了信息。本研究建立了一个基于构成方程的现象学模型，用于预测使用金属注射成型原料通过 ME3DP 制造的纯铜部件在烧结过程中的密度和结构变形。通过在垂直扩张仪中进行等温阶梯加热循环，利用收缩率估算确定了致密化率。此外，为了估算铜的轴向粘度，还在垂直扩张仪中以 850、900、950、1000 和 1050°C 的长等温加热循环对探针进行了不同的负载实验。考虑到各向同性假设，使用 COMSOL Multiphysics 中带有用户定义蠕变的固体力学模块求解了构成方程。在预测烧结过程中的收缩和变形时，使用了立方体和悬挂 I 截面两种几何形状。根据烧结过程中的收缩和重力导致的结构变形，所开发的模型成功预测了相对密度。

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引用次数: 0

Magnetic imaging of thermally switchable antiferromagnetic/ferromagnetic modulated thin films 热转换反铁磁/铁磁调制薄膜的磁成像

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-28 DOI: 10.1016/j.actamat.2024.120515

W. Griggs , A. Peasey , F. Schedin , Md.S. Anwar , B. Eggert , M.-A. Mawass , F. Kronast , H. Wende , R. Bali , T. Thomson

Nanoscale magnetic patterning can lead to the formation of a variety of spin textures, depending on the intrinsic properties of the material and the microstructure. Here we report on the spin textures formed in laterally patterned antiferromagnetic (AF)/ferromagnetic (FM) thin film stripes with a period of 200 nm (100 nm FM/100 nm AF). We make use of the AF to FM phase transition in FeRh thin films at ∼100 °C, thereby creating a nanoscale pattern that is thermally switchable between AF/FM stripes and uniformly FM. A combination of spin-resolved photoemission electron microscopy, magnetic force microscopy, and magnetometry measurements allow direct nanoscale observations of the stray magnetic fields emergent from the nanopattern as well as the underlying magnetisation. Our measurements reveal pinning centres resistant to temperature cycling that govern the modulated spin-texture as well as a sub-texture consisting of grain-driven nanoscale magnetisation structure directed out of the film plane. The nanoscale magnetic structure is thus strongly influenced by the film microstructure. Signatures of exchange bias are not observed, most likely due to the small contact area between the AF and FM regions, combined with the fact that the interfaces between the damaged and undamaged regions are likely to be highly diffuse owing to the lateral scattering of incoming ions. These results show that temperature controllable spin textures can be created in FeRh thin films which could find application in domain wall, microwave, or magnonic devices.

根据材料的内在特性和微观结构，纳米级磁性图案化可形成各种自旋纹理。在此，我们报告了在周期为 200 nm 的横向图案化反铁磁 (AF) / 铁磁 (FM) 薄膜条纹（100 nm FM/100 nm AF）中形成的自旋纹理。我们利用了 FeRh 薄膜在 ∼100°C 时从 AF 到 FM 的相变，从而创造出一种可在 AF/FM 条纹和均匀 FM 之间热切换的纳米级图案。结合自旋分辨光电发射电子显微镜、磁力显微镜和磁力测量法，可以直接从纳米尺度观察纳米图案产生的杂散磁场以及底层磁化。我们的测量结果揭示了可抵御温度循环的引脚中心，该引脚中心控制着调制的自旋纹理以及由晶粒驱动的纳米级磁化结构组成的子纹理，该磁化结构指向薄膜平面之外。因此，纳米级磁性结构深受薄膜微观结构的影响。没有观察到交换偏压的迹象，这很可能是由于 AF 和 FM 区域之间的接触面积较小，再加上由于传入离子的横向散射，损坏区域和未损坏区域之间的界面很可能是高度弥散的。这些结果表明，在 FeRh 薄膜中可以产生温度可控的自旋纹理，可应用于畴壁、微波或磁性器件。

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引用次数: 0

A novel approach to coating for improving the comprehensive high-temperature service performance of TiAl alloys 改善钛铝合金高温综合服役性能的新型涂层方法

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-28 DOI: 10.1016/j.actamat.2024.120500

Yanxun Mu , Yongfeng Liang , Jiaqi Sheng , Chenyang Zhang , Zheng Guo , Gang Yang , Tielong Sun , Yongsheng Wang , Junpin Lin

TiAl alloys, with half the density of nickel-based superalloys, are highly suitable for aerospace applications requiring lightweight materials. However, they tend to form a nonprotective mixed oxide film on their surface at high temperatures. This oxide film is prone to cracking, which can lead to long-term high-temperature oxidation surface degradation, thereby reducing their high-temperature creep and fatigue resistance. Surface cracks on the oxide film further aggravated the brittleness of the TiAl intermetallic compounds after high-temperature exposure. While coatings are typically applied to promote the formation of dense oxides for surface protection, they primarily enhance oxidation resistance. However, this improvement comes at the cost of reducing the high-temperature creep and fatigue resistance and the room-temperature plasticity of TiAl alloys. This study introduced an electroless coating method to deposit a Pt coating, approximately 200 nm thick, on the surface of TiAl alloys. During high-temperature applications, the Pt dispersed as nanoparticles within the oxide layer, enhancing the oxide's plasticity. This oxide structure considerably improved the high-temperature creep and fatigue properties of TiAl alloys, while enhancing their room-temperature tensile properties after oxidation. This approach offers a novel strategy for designing surface coatings for high-temperature components.

TiAl 合金的密度只有镍基超级合金的一半，非常适合需要轻质材料的航空航天应用。然而，在高温条件下，它们的表面往往会形成一层非保护性的混合氧化膜。这种氧化膜容易开裂，会导致长期高温氧化表面退化，从而降低其高温蠕变和抗疲劳性能。氧化膜上的表面裂纹进一步加剧了高温暴露后 TiAl 金属间化合物的脆性。虽然涂层通常是为了促进致密氧化物的形成以达到表面保护的目的，但其主要作用是增强抗氧化性。然而，这种改善是以降低 TiAl 合金的高温抗蠕变性、抗疲劳性和室温塑性为代价的。本研究引入了一种无电镀涂层方法，在钛铝合金表面沉积一层约 200 nm 厚的铂涂层。在高温应用过程中，铂以纳米颗粒的形式分散在氧化层中，增强了氧化物的可塑性。这种氧化物结构大大改善了钛铝合金的高温蠕变和疲劳性能，同时提高了氧化后的室温拉伸性能。这种方法为设计高温部件的表面涂层提供了一种新策略。

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引用次数: 0

Enhanced energy storage performance of 0.85BaTiO3–0.15Bi(Mg0.5Hf0.5)O3 films via synergistic effect of defect dipole and oxygen vacancy engineering 通过缺陷偶极和氧空位工程的协同效应提高 0.85BaTiO3-0.15Bi(Mg0.5Hf0.5)O3 薄膜的储能性能

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-28 DOI: 10.1016/j.actamat.2024.120522

Weijie Fu , Yi-qin Lu , Qiuyang Han , Tian-Yi Hu , Tingzhi Duan , Yupeng Liu , Shao-Dong Cheng , Yanzhu Dai , Ming Liu , Chunrui Ma

Dielectric capacitors are widely used in electronic devices due to their ultra-fast charge/discharge rate and ultra-high power density, but their lower energy density and poor thermal stability limit their further application. In contrast to the traditional strategy of suppressing defects, this work combines oxygen vacancies with defect dipoles to improve the breakdown strength and polarization behavior of ferroelectric films. Low concentration of oxygen vacancies and defect dipoles can trap charge carriers and increase breakdown strength, but if the concentration is too high, it can easily make films prone to breakdown. Moreover, the defect dipoles can reduce P_r by providing intrinsic restoring force for polarization switching, while excessive defect dipoles and oxygen vacancies can pin domain walls and increase P_r. By delicately controlling the concentration of oxygen vacancies and defect dipoles in the film, the BT-BMH film deposited at 0.135 mbar achieved the maximum breakdown strength and slim P-E loops, inducing the energy density to reach 108.9 J·cm^-3 with an efficiency of 79.6 % at room temperature and excellent thermal stability in the wide temperature range of -100∼350 °C with the energy density of 69.1 J·cm^-3. This work reveals the important significance of reasonable defect control for improving energy storage performance and provides an effective method for developing high-performance dielectric capacitors.

电介质电容器因其超快的充放电速度和超高的功率密度而被广泛应用于电子设备中，但其较低的能量密度和较差的热稳定性限制了其进一步的应用。与抑制缺陷的传统策略不同，这项研究将氧空位与缺陷偶极子相结合，以改善铁电薄膜的击穿强度和极化行为。低浓度的氧空位和缺陷偶极子可以捕获电荷载流子并提高击穿强度，但如果浓度过高，则容易使薄膜发生击穿。此外，缺陷偶极子能为极化转换提供内在恢复力，从而降低镨值，而过多的缺陷偶极子和氧空位则会钉住畴壁，增加镨值。通过微妙地控制薄膜中氧空位和缺陷偶极子的浓度，在 0.135 毫巴条件下沉积的 BT-BMH 薄膜获得了最大的击穿强度和纤细的 P-E 环，使能量密度达到 108.9 J-cm-3，室温下的效率为 79.6%，并在 -100∼350 °C 的宽温度范围内具有优异的热稳定性，能量密度为 69.1 J-cm-3。这项工作揭示了合理控制缺陷对提高储能性能的重要意义，为开发高性能电介质电容器提供了一种有效方法。

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引用次数: 0

New insights into the partitioning behavior of Mo in nickel-based superalloys and its effect on microstructure using CALPHAD-assisted phase field modeling 利用 CALPHAD 辅助相场建模对镍基超合金中钼的分配行为及其对微观结构影响的新认识

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-28 DOI: 10.1016/j.actamat.2024.120510

Zexin Wang , Chuanxin Liang , Xiangdong Ding , Dong Wang

Elemental partitioning behaviors are critical in determining the high-temperature capabilities of superalloys. In multi-component superalloys, these behaviors are influenced by the competition among elements. This study examines the effects of Cr concentration on elemental distribution behaviors and γ′ evolution in Ni–10Al–4Mo–xCr superalloys using CALPHAD-informed phase field modeling. Our simulations show that Mo's preference shifts from γ′ precipitates to γ matrix as Cr concentration increases. This shift results from the competitive interactions between Mo and Cr atoms at the corner sites of Ni₃Al, reducing Mo's solubility in γ′ precipitates. Further analysis reveals that with increasing Cr concentration, more Mo is displaced by Cr at the B sites of γ′-A₃B. Additionally, the Mo content in γ′ precipitate decreases with rising Cr content, resulting in an abnormal rise in the γ′ volume fraction based on Mo mass balance. Moreover, γ′ coarsening rate initially rises and then falls with increasing Cr concentration in an inverted “V” shape, a change attributable to variations in the γ matrix supersaturation. These findings provide new insights into Mo distribution in nickel-based superalloys and offer guidance for designing superalloys with improved microstructural stability.

元素分配行为是决定超级合金高温性能的关键。在多组分超耐热合金中，这些行为受到元素间竞争的影响。本研究采用 CALPHAD 为基础的相场建模，研究了铬浓度对 Ni-10Al-4Mo-xCr 超合金中元素分布行为和 γ′ 演变的影响。模拟结果表明，随着铬浓度的增加，钼的偏好从γ′沉淀转移到γ基体。这种转变是由于镍3Al角位上的钼原子和铬原子之间的竞争性相互作用降低了钼在γ′沉淀中的溶解度。进一步的分析表明，随着铬浓度的增加，γ′-A3B 的 B 位上有更多的钼被铬取代。此外，γ′沉淀中的钼含量随着铬含量的增加而减少，导致基于钼质量平衡的γ′体积分数异常上升。此外，随着铬浓度的增加，γ′粗化率先上升后下降，呈倒 "V "形，这种变化可归因于γ基体过饱和度的变化。这些发现为了解镍基超合金中 Mo 的分布提供了新的视角，并为设计具有更好微观结构稳定性的超合金提供了指导。

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引用次数: 0

Enabling quantitative analysis of in situ TEM experiments: A high-throughput, deep learning-based approach tailored to the dynamics of dislocations 实现原位 TEM 实验的定量分析：基于深度学习的高通量方法，专为位错动力学量身定制

IF 8.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2024-10-28 DOI: 10.1016/j.actamat.2024.120455

Hengxu Song , Binh Duong Nguyen , Kishan Govind , Dénes Berta , Péter Dusán Ispánovity , Marc Legros , Stefan Sandfeld

In situ TEM is by far the most commonly used microscopy method for imaging dislocations, i.e., line-like defects in crystalline materials. However, quantitative image analysis so far was not possible, implying that also statistical analyses were strongly limited. In this work, we created a deep learning-based digital twin of an in situ TEM straining experiment, additionally allowing to perform matching simulations. As application we extract spatio-temporal information of moving dislocations from experiments carried out on a Cantor high entropy alloy and investigate the universality class of plastic strain avalanches. We can directly observe “stick–slip motion” of single dislocations and compute the corresponding avalanche statistics. The distributions turn out to be scale-free, and the exponent of the power law distribution exhibits independence on the driving stress. The introduced methodology is entirely generic and has the potential to turn meso-scale TEM microscopy into a truly quantitative and reproducible approach.

原位 TEM 是目前最常用的显微镜成像方法，用于对位错（即晶体材料中的线状缺陷）进行成像。然而，迄今为止还无法进行定量图像分析，这意味着统计分析也受到很大限制。在这项工作中，我们创建了一个基于深度学习的原位 TEM 应变实验数字孪生模型，还可以进行匹配模拟。作为应用，我们从康托高熵合金实验中提取了移动位错的时空信息，并研究了塑性应变雪崩的普遍性。我们可以直接观察单个位错的 "粘滑运动"，并计算相应的雪崩统计量。结果表明，雪崩分布是无标度的，幂律分布的指数与驱动应力无关。所介绍的方法完全通用，有可能将介观尺度 TEM 显微镜变成一种真正定量和可重复的方法。

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引用次数: 0