Acta Materialia最新文献

Overcoming high-strength instability in magnesium-lithium alloys via concomitant precipitation of dual stable nano-phases 通过双稳定纳米相的同时析出克服镁锂合金高强不稳定性

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-10 DOI: 10.1016/j.actamat.2026.122010

Lang Yu , Mengran Zhou , Yuxuan Chen , Fan Ji , Song Tang , Yuhong Zhao , Xiaopei Zhang , Wenhan Yu , Jing Dong , Hongyan Xia , Luqing Cui , Qingyu Shi , Huijun Kang , Enyu Guo , Mingxin Huang , Jinchuan Jie , Xiaoyan Li , Tongzheng Xin

Body-centered cubic Mg-Li-Al alloys are noted for their exceptional specific strength and ductility. However, the rapid coarsening of Mg₃Al nanoprecipitates formed after solution treatment and water quenching leads to significant strength degradation at room temperature. To suppress this instability, we propose an alloy composition optimization strategy that promotes the transformation of Mg₃Al into more stable semi-coherent Mg(Al, Zn, Ag)Li₂ precipitates, accompanied by the co-precipitation of Li-rich clusters at the interface. To systematically reveal the evolution pathway and underlying mechanisms of the D0₃-ordered precipitates under this compositional design, we employed a combined approach utilizing synchrotron X-ray diffraction and phase-field simulations. First-principles calculations confirm that the Mg(Al, Zn, Ag)Li₂ phase has a more negative formation enthalpy than the Mg₃Al phase, indicating greater stability at room temperature. The presence of Li-rich clusters helps retain the BCC structure of the alloy and suppresses the transformation of the matrix to HCP. Molecular dynamics simulations reveal that Mg(Al, Zn, Ag)Li₂ and Li-rich clusters cooperatively induce an interfacial stress field, which hinders dislocation motion and enhances dislocation interactions, thereby significantly improving strength. Simultaneously, the Li-rich clusters reduce coherent interfacial stress and slow precipitate coarsening, effectively compensating for strength loss and maintaining excellent structural stability under high-strength conditions.

体心立方Mg-Li-Al合金以其特殊的比强度和延展性而闻名。然而，固溶处理和水淬后形成的Mg3Al纳米沉淀迅速变粗，导致室温下强度显著下降。为了抑制这种不稳定性，我们提出了一种合金成分优化策略，该策略可以促进Mg3Al向更稳定的半相干Mg(Al, Zn, Ag)Li2相转变，并伴随着界面处富li团簇的共析出。为了系统地揭示d03有序析出相在这种成分设计下的演化途径和潜在机制，我们采用同步加速器x射线衍射和相场模拟相结合的方法。第一性原理计算证实，Mg(Al, Zn, Ag)Li2相比Mg3Al相具有更负的生成焓，在室温下具有更大的稳定性。富锂团簇的存在有助于保持合金的BCC结构，抑制基体向HCP的转变。分子动力学模拟表明，Mg(Al, Zn, Ag)Li2和富li团簇共同诱导界面应力场，抑制位错运动，增强位错相互作用，从而显著提高强度。同时，富锂团簇降低了共格界面应力，减缓了析出物的粗化，有效补偿了强度损失，并在高强度条件下保持了优异的结构稳定性。

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引用次数: 0

Magnetic and ferroelectric control over spontaneous valley polarization in ScO2RuCl-based room-temperature ferrovalley and multiferroic semiconductors 基于sco2rucl的室温铁谷和多铁性半导体中自发谷极化的磁和铁电控制

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-12 DOI: 10.1016/j.actamat.2026.122013

Hai-Nan Zhang , Yun-Jing Zhao , Bokai Zhang, Zhi-Yong Wang

The reversible manipulation of spontaneous room-temperature (RT) valley polarization bears great promise in nonvolatile information storage and processing, yet such experimental realization remains an unresolved challenge. By first-principles and Monte Carlo simulations, monolayer ScO

_{2}

RuCl is predicted to be an ideal ferrovalley semiconductor with robust Ising ferromagnetism above-RT against the in-plane biaxial strains reachable in experiments, whose nonvolatile valley polarization in the ultraclean limit higher one order of magnitude than RT thermal disturbance can be inverted by spin-flip transition. The spin–orbital coupling Hamiltonian quite well captures the switchable valley physics. More intriguingly, we appreciate convertible above-RT out-of-plane ferroelectric polarization through interlayer sliding in bistable A-type Ising antiferromagnetically coupled ScO

_{2}

RuCl bilayers with an ultralow switching barrier and an ultrahigh Néel temperature. Resultant giant sliding ferroelectricity can manipulate the saturated valley polarization unprecedentedly up to the monolayer limit in a reversible and nonvolatile means. These native RT merits are further found to be immune to moderate compressive strains along the out-of-plane direction. Overall, the switchable valley polarization in response to the direction of either magnetization or ferroelectricity under complicated mechanical environments endows the appealing ScO

_{2}

RuCl-based ferrovalley and multiferroic semiconductors with tremendous potential for direct commercial applications of RT polarized electronics.

自发室温谷极化的可逆操纵在非易失性信息存储和处理中具有很大的前景，但这种实验实现仍然是一个未解决的挑战。通过第一性原理和蒙特卡罗模拟，预测单层ScO22RuCl是一种理想的铁谷半导体，在实验可达到的平面内双轴应变下，在RT以上具有鲁棒的Ising铁磁性，其在超净极限下的非挥发性谷极化比RT高一个数量级，可以通过自旋翻转转变来逆转热扰动。自旋轨道耦合哈密顿量很好地描述了可切换谷物理。更有趣的是，我们在具有超低开关势垒和超高n温度的双稳态a型Ising反铁磁耦合ScO22RuCl双层中发现了通过层间滑动可转换的rt以上面外铁电极化。由此产生的巨大滑动铁电可以前所未有地以可逆和非挥发的方式将饱和谷极化控制到单层极限。进一步发现这些固有的RT优点对沿面外方向的中等压缩应变免疫。总的来说，在复杂的机械环境下，响应磁化或铁电方向的可切换谷极化赋予了诱人的基于sco22rucl的铁谷和多铁性半导体在RT极化电子的直接商业应用方面具有巨大的潜力。

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引用次数: 0

FCC-HCP phase transition in ultrathin gold films: A first-principles investigation 超薄金薄膜中的FCC-HCP相变：第一性原理研究

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-06 DOI: 10.1016/j.actamat.2026.122000

Jun Pei , Tong Zhang , Tao Liu , Yuanbiao Tong , Pan Wang , Binglun Yin , Yang Gao

Gold with the unconventional hexagonal close-packed (HCP) phase shows outstanding optical and mechanical properties, holding immense promises for optoelectronic applications. Ultrathin HCP gold films can be fabricated by reducing the thickness of the bulk face-centered cubic (FCC) precursor to a few nanometers, but the fundamental mechanism governing the thickness-dependent FCC→HCP phase transition remains insufficiently investigated. Herein, density functional theory (DFT) calculations and high-resolution transmission electron microscopy (HRTEM) are employed to elucidate the physical origin of the FCC→HCP phase transition in ultrathin gold films. DFT calculations demonstrate that in-plane compressive strain is a determining factor in facilitating the FCC→HCP phase transition, with a critical in-plane compressive strain of 2 ∼ 3 % (corresponding to a lattice constant of ∼ 2.8 Å). HRTEM measurements confirm the accessibility of such compressive strain. The intrinsic compressive strain in gold thin films is approximately 1 % and becomes more pronounced as the thickness decreases. The extrinsic compressive strain may arise from residual strain and substrate epitaxial strain induced during the fabrication process. Further DFT study of the kinetics of the phase transition reveals that in-plane compressive strain effectively modulates the stacking fault energy and transition pathways. Our findings establish a foundation for the structural manipulation and fabrication of advanced nanometals.

具有非常规六方密堆积（HCP）相的金显示出出色的光学和机械性能，在光电应用中具有巨大的前景。将体积面心立方（FCC）前驱体的厚度减小到几纳米，可以制备超薄HCP金膜，但控制FCC→HCP相变的基本机制仍未得到充分的研究。本文利用密度泛函理论（DFT）计算和高分辨率透射电镜（HRTEM）分析了超薄金膜中FCC→HCP相变的物理成因。DFT计算表明，面内压缩应变是促进FCC→HCP相变的决定性因素，其临界面内压缩应变为2 ~ 3%（对应于晶格常数为~ 2.8 Å）。HRTEM测量证实了这种压缩应变的可及性。金薄膜的本征压缩应变约为1%，随厚度的减小而增大。外部压缩应变可能来自于制造过程中产生的残余应变和衬底外延应变。对相变动力学的进一步DFT研究表明，面内压缩应变有效地调节了层错能和相变路径。我们的发现为结构操纵和先进纳米金属的制造奠定了基础。

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引用次数: 0

Fragile-to-strong transition in liquid As2S3 under pressure: The effect of melt metallization 压力下液态As2S3从脆弱到强的转变：熔融金属化的影响

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-06 DOI: 10.1016/j.actamat.2026.122001

Vadim V. Brazhkin , Oleg B. Tsiok , Andrey Tverjanovich , Takeshi Usuki , Chris J. Benmore , Maxim Khomenko , Anton Sokolov , Mohammad Kassem , Daniele Fontanari , Koji Ohara , Eugene Bychkov

The well-known classification of glass-forming melts into fragile and strong liquids has several notable exceptions, including water, silica, and certain phase-change materials (PCMs). These exceptional fluid systems exhibit a fragile-to-strong transition (FST) upon cooling: a transformation from a high-temperature liquid with fast atomic dynamics, low viscosity, and low flow activation energy, to a viscous supercooled melt with high energy barriers near the glass transition temperature

T_{g}

. This behavior is critically important for non-volatile memories, photonic tensor cores, reconfigurable metamaterials, and other devices, that use PCMs, enabling nanosecond-scale crystallization in the fragile regime and long data retention in the strong regime near or below

T_{g}

. A significant structural transformation is expected between these two viscosity regimes, along with a semiconductor-metal (SC-M) transition upon heating, driven by high internal pressure and associated density increase. By applying high external pressure to the canonical low-conducting chalcogenide melt As₂S₃, we observed both the FST and the SC-M transition, occurring simultaneously within the same domain of the

P, T

−phase space. These findings suggest that the FST is not limited to a few exceptional liquids but is a common phenomenon, at least in systems that exhibit melt metallization within specific regions of their

P, T

−phase diagrams.

众所周知的玻璃成型熔体易碎和强液体的分类有几个明显的例外，包括水，二氧化硅和某些相变材料（pcm）。这些特殊的流体系统在冷却时表现出从脆弱到强大的转变（FST）：从具有快速原子动力学、低粘度和低流动活化能的高温液体转变为具有高能量屏障的粘性过冷熔体，接近玻璃化转变温度Tg。这种行为对于使用pcm的非易失性存储器、光子张量核、可重构超材料和其他器件至关重要，可以在脆弱区实现纳秒级的结晶，在接近或低于Tg的强区实现长时间的数据保留。在高内压和相关密度增加的驱动下，这两种粘度状态之间预计会发生重大的结构转变，同时在加热时发生半导体-金属（SC-M）转变。通过对典型低导电硫系熔体As2S3施加高压，我们观察到FST和SC-M转变同时发生在P，T−相空间的同一域内。这些发现表明，FST并不局限于少数特殊的液体，而是一种普遍现象，至少在P，T -相图的特定区域内表现出熔融金属化的系统中是如此。

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引用次数: 0

Harnessing laser-induced in-situ nanowhiskers for high-strength aluminum alloys via additive manufacturing 利用增材制造技术利用激光诱导原位纳米晶须制备高强度铝合金

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-05 DOI: 10.1016/j.actamat.2026.121987

Haoran Yang , Xiangren Bai , Dongdong Zhao , Junwei Sha , Xudong Rong , Zehao Rong , Feng Qian , Shiwei Pan , Jianglin Lan , Xiang Zhang , Chunnian He , Naiqin Zhao

The crafting of lightweight and strong aluminum alloys by additive manufacturing has long relied on expensive metal elements like Sc, Zr etc. to achieve high strength, which severely hinders their widespread applications. Here we report a costly-element-free strategy that leverages the extreme thermal gradients and laser-induced recoil pressure in laser powder bed fusion (LPBF) to in situ synthesize dense and uniformly-dispersed MgAlB₄ nano-whiskers within Al alloy matrix. Featuring diameters of 5–15 nm and aspect ratios exceeding 20, the nano-whiskers efficaciously eliminate solidification cracking and porosity, enabling near-full densification (∼99.99%) and an ultrafine equiaxed grain structure (∼1.3 μm). Marked dislocation-whisker interactions are enabled by the high aspect ratios of the nano-whiskers and their robust interfacial bonding with the Al matrix. Quasi-continuous nano-whisker networks in matrix not only promote dislocation storage and multiplication, but also allows for dislocation bypassing perpendicular to the axial direction of whiskers. The alloy thus achieves an ultimate tensile strength of ∼610 MPa and a uniform elongation of ∼8.0%. This work offers a scalable pathway toward the design and development of cost-effective, high-performance aluminum alloys by additive manufacturing.

长期以来，通过增材制造制造轻质强铝合金依赖于Sc、Zr等昂贵的金属元素来实现高强度，这严重阻碍了其广泛应用。在这里，我们报告了一种昂贵的无元素策略，利用激光粉末床熔合（LPBF）中的极端热梯度和激光诱导的反冲压力，在铝合金基体中原位合成致密且均匀分散的MgAlB4纳米晶须。纳米晶须直径为5-15 nm，长径比超过20，有效地消除了凝固裂纹和孔隙，实现了近乎完全致密化（~ 99.99%）和超细等轴晶粒结构（~ 1.3 μm）。由于纳米晶须的高长宽比及其与Al基体的强大界面结合，使得位错与晶须的相互作用成为可能。基体中的准连续纳米晶须网络不仅促进位错的储存和增殖，而且允许位错在垂直于晶须轴向的方向上绕过。因此，该合金的极限抗拉强度为~ 610 MPa，均匀伸长率为~ 8.0%。这项工作为通过增材制造设计和开发具有成本效益的高性能铝合金提供了一条可扩展的途径。

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引用次数: 0

Towards a solute-engineering strategy for achieving excellent corrosion resistance in weathering steel 实现耐候钢优异耐蚀性的溶质工程策略

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-05 DOI: 10.1016/j.actamat.2026.121988

X.H. Liu , X.Y. Cui , C.L. Jiang , S.P Ringer , G. Sha

Enhancing corrosion resistance in weathering steels requires understanding how alloying elements capture corrosive species. Here, we investigate a Sb-bearing weathering steel exposed to SO₂-rich environments for up to 12 months using multiscale characterization and density functional theory calculation. The ultrafine-grained layer (UGL) and transition layer (TL) are identified as key barriers protecting the steel substrate. Advanced microscopy and microanalysis reveal that Sb, P, Cu, and Si correlate positively with S within Cr-rich oxide nanoparticles at grain boundaries (GBs) of the UGL. Enrichment of Cr, Ni, Sb, P, and Cu in these layers promotes efficient S trapping. Furthermore, segregation of Cr, Sb, P, Si, and Cu at UGL GBs captures both O and S ions through nanoparticle formation, suppressing their diffusion toward the substrate. These results demonstrate a solute engineering strategy: tailoring Cr, Sb, P, Si, and Cu enrichment in the UGL and its GBs to establish robust corrosion barriers in aggressive environments.

提高耐候钢的耐腐蚀性需要了解合金元素如何捕获腐蚀性物质。在这里，我们使用多尺度表征和密度泛函理论计算，研究了一种含锑耐候钢暴露在富含二氧化硫的环境中长达12个月。超细晶层（UGL）和过渡层（TL）是保护钢基体的关键屏障。先进的显微镜和微量分析表明，Sb、P、Cu和Si在UGL晶界（GBs）的富cr氧化物纳米颗粒中与S呈正相关。Cr, Ni, Sb， P和Cu在这些层中的富集促进了有效的S捕获。此外，Cr、Sb、P、Si和Cu在UGL gb中的偏析通过形成纳米颗粒捕获O和S离子，抑制它们向衬底的扩散。这些结果表明了一种溶质工程策略：调整UGL及其gb中Cr、Sb、P、Si和Cu的富集程度，以在腐蚀性环境中建立坚固的腐蚀屏障。

引用次数: 0

On pipe diffusion of rhenium along misfit-dislocation-networks in Ni-base single crystal superalloys ni基单晶高温合金中铼沿错配-位错网络的管状扩散

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2025-10-19 DOI: 10.1016/j.actamat.2025.121656

Rico Zehl , Nicolas Karpstein , Aparna Saksena , Oliver Martin Horst , Aleksander Kostka , Baptiste Gault , Alfred Ludwig , Suzana G. Fries , Erdmann Spiecker , Guillaume Laplanche , Gunther Eggeler

This study explores whether the diffusion of Re in the γ-phase of Ni-base superalloy single crystals is accelerated along fine dislocation networks that have formed at γ/γʹ-interfaces during high-temperature and low-stress creep. Diffusion couples of Re-enriched superalloy thin films were sputter deposited onto (100) planes of two Re-free single-crystalline nickel-base superalloys with different microstructures. One consisted of an as-processed microstructure with cuboidal γʹ-particles separated by thin γ-channels, with a low dislocation density. The other featured continuous γʹ-rafts parallel to the [100] direction with fine dislocation networks at the γ/γʹ-interfaces. The rafted structure was produced by 2 % creep deformation along the [001] direction at 1000 °C and 240 MPa. Analytical transmission electron microscopy and atom probe tomography revealed that the diffusion of Re into the γ-phase was not accelerated by the presence of dislocation networks at the γ/γʹ-interfaces of the rafted microstructure.

本研究探讨了高温低应力蠕变过程中，Re在ni基高温合金单晶γ相中的扩散是否沿着γ/γ′-界面形成的精细位错网络加速。在两种不同组织的无re单晶镍基高温合金的（100）平面上溅射沉积了富re高温合金薄膜的扩散偶。一种是加工后的微观结构，由细γ-通道隔开的立方γ-颗粒，具有低的位错密度。另一种是平行于[100]方向的连续γ′筏，在γ′/γ′界面处有精细的位错网络。在1000℃、240 MPa条件下，沿[001]方向进行2%蠕变，形成筏状组织。分析透射电镜和原子探针层析成像显示，在筏形微观结构的γ/γ′-界面处存在位错网络并没有加速Re向γ相的扩散。

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引用次数: 0

Achieving superior high-temperature strength–ductility synergy in a Cu–Ag–Zr alloy via trace Ce doping induced atomic substitution and precipitate refinement 通过微量Ce掺杂诱导原子取代和析出相细化，实现Cu-Ag-Zr合金优异的高温强度-延展性协同作用

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-10 DOI: 10.1016/j.actamat.2026.122011

Xiang Wu, Wenfeng Pang, Tianle Li, Jingxia Sun, Xiaochun Liu

High-conductivity copper alloys often suffer from severe degradation in strength and ductility at elevated temperatures, limiting their applications under extreme thermal conditions. Here, we demonstrate that the addition of a trace amount of Ce (0.2 wt. %) to a Cu–Ag–Zr alloy leads to exceptional high-temperature mechanical properties without significantly compromising thermal conductivity. Ce efficiently scavenges free oxygen and metallic impurities, leading to grain boundary purification and dispersion strengthening through nano-sized rare earth oxide particles. Consequently, this significantly improves the alloy's high-temperature strength and ductility while preserving its high thermal conductivity. Concurrently, the addition of Ce refines submicron secondary phase particles and increases their number density, resulting in a substantial decrease in the final grain size due to the recrystallization of PSN nuclei. Furthermore, Ce suppresses both discontinuous precipitation and coarsening of nanoscale Ag precipitates, thereby reinforcing the Zener pinning effect of the secondary phase on grain boundaries and inhibiting grain coarsening during recrystallization. These mechanisms work together to refine the grains, prevent grain coarsening during heating, and enhance the high-temperature mechanical properties of the alloy. This work establishes a viable strategy for optimizing the high-temperature performance of Cu–Ag–Zr alloys without compromising thermal conductivity, offering direct guidance for their application in high temperature service environments.

在高温下，高导电性铜合金的强度和延展性往往会严重退化，这限制了它们在极端热条件下的应用。在这里，我们证明了在Cu-Ag-Zr合金中添加微量的Ce （0.2 wt. %）可以在不显著影响导热性的情况下获得优异的高温机械性能。Ce通过纳米级的稀土氧化物颗粒有效地清除游离氧和金属杂质，实现晶界净化和弥散强化。因此，这大大提高了合金的高温强度和延展性，同时保持其高导热性。同时，Ce的加入细化了亚微米次级相颗粒，增加了它们的数量密度，导致PSN核的再结晶导致最终晶粒尺寸大幅减小。此外，Ce抑制了纳米级银相的不连续析出和粗化，从而增强了二次相在晶界上的齐纳钉钉效应，抑制了再结晶过程中晶粒的粗化。这些机制共同作用，细化晶粒，防止晶粒在加热过程中变粗，提高合金的高温力学性能。本研究为Cu-Ag-Zr合金在不影响导热性的情况下优化高温性能建立了一种可行的策略，为其在高温服务环境中的应用提供了直接指导。

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引用次数: 0

Predicting Interstitial Solutes in Refractory Complex Concentrated Alloys via a Combined Experimental and Computational Workflow: A Case Study on Oxygen in NbTaTiHf 用实验和计算相结合的方法预测难熔复杂浓缩合金中的溶质：以NbTaTiHf中的氧为例

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-12 DOI: 10.1016/j.actamat.2026.122019

Aomin Huang , Siya Zhu , Calvin Belcher , Ryker Rigsby , Diran Apelian , Raymundo Arróyave , Enrique J. Lavernia

Refractory complex concentrated alloys (RCCAs), composed of multiple principal refractory elements, are promising candidates for high-temperature structural applications due to their exceptional thermal stability and high melting points. However, their mechanical performance is often compromised by interstitial impurities—particularly oxygen, nitrogen, and carbon—which segregate to grain boundaries and promote embrittlement. In this study, we investigate the solubility and thermodynamic behavior of oxygen interstitials in a model Nb₄₅Ti₂₅Hf₁₅Ta₁₅ RCCA system. We synthesized (Nb₄₅Ti₂₅Hf₁₅Ta₁₅)_100-xO_x alloys with varying oxygen contents (x=0–5 at.%) via plasma arc melting and characterized their phase evolution and microstructure using XRD, SEM, and TEM. Complementary computational modeling was performed using machine-learning interatomic potentials (MLIPs) integrated with Monte Carlo simulations to probe oxygen interactions at the atomic scale. Our results reveal an effective solubility limit for oxygen between 0.8 and 1.0 at.%, beyond which HfO₂ formation is energetically favorable. This combined experimental–computational framework provides a predictive approach for managing interstitial behavior in RCCAs, enabling improved alloy design strategies for enhanced mechanical performance.

由多种主要耐火元素组成的难熔复合浓缩合金（RCCAs）由于其优异的热稳定性和高熔点，在高温结构应用中具有广阔的应用前景。然而，它们的机械性能经常受到间隙杂质的影响，特别是氧、氮和碳，这些杂质会偏析到晶界并促进脆化。在本研究中，我们研究了氧隙在Nb45Ti25Hf15Ta15 RCCA体系中的溶解度和热力学行为。我们合成了不同氧含量（x= 0-5 at）的（Nb45Ti25Hf15Ta15）100-xOx合金。通过等离子体电弧熔炼，并利用XRD、SEM和TEM对其相演化和微观结构进行了表征。利用机器学习原子间电位（MLIPs）与蒙特卡罗模拟相结合，进行了互补的计算建模，以探测原子尺度上的氧相互作用。我们的结果表明，氧的有效溶解度限制在0.8和1.0 at之间。%，超过这个值HfO₂的形成在能量上是有利的。这种结合实验-计算的框架为管理rcca中的间隙行为提供了一种预测方法，从而改进了合金设计策略，提高了机械性能。

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引用次数: 0

Interplay of dynamic strain aging and dynamic precipitation in the Portevin–Le Châtelier effect in an Al-Mg-Zn-based crossover aluminum alloy 动态应变时效与动态析出在al - mg - zn基交叉铝合金Portevin-Le chaltelier效应中的相互作用

IF 9.3 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-04-15 Epub Date: 2026-02-05 DOI: 10.1016/j.actamat.2026.121990

Xiuzhen Zhang , Yue Li , Shaolou Wei , Haonan Guo , Zhufeng He , Chao Yang , Wu Gong , Stefanus Harjo , Dengshan Zhou , Zhihui Li , Deliang Zhang , Dierk Raabe , Gaowu Qin

Dynamic strain aging (DSA), a phenomenon prevalent in many metallic alloys, arises from interactions between mobile solute atoms and dislocations. At certain temperatures and strain rates, these interactions cause strain localization beyond critical strains, manifesting as serrations in stress-strain curves — known as the Portevin–Le Châtelier (PLC) effect. While current DSA models focus on edge dislocations interacting with solutes, implicitly attributing the PLC effect to aged edge dislocations, in this work, we highlight a critical role for screw dislocations. Through systematic tensile testing of an Al-Mg-Zn-based crossover solid-solution alloy at room temperature for strain rates ranging from 0.00005 to 0.1 s⁻¹, we demonstrate that DSA and strain-induced dynamic precipitation concurrently govern the serration behavior. At low strain rates (e.g. 0.0001 s⁻¹), DSA-assisted precipitation leads to Type C serrations at larger strains, whereas high strain rates (e.g. 0.1 s⁻¹) suppress precipitation (i.e. sole DSA), resulting in Type A serrations at lower strains. High-energy X-ray diffraction analysis shows screw dislocations dominating early deformation, and decreasing in proportion as strain increases. Transmission electron microscopy probing reveals suppressed cross-slip and plastic flow localization at 0.0001 s⁻¹. At 0.1 s⁻¹, however, frequent cross-slip initiates early dislocation microbands that expand laterally. Screw dislocations within these microbands drive Type A serrations — demonstrating their primary role, not edge dislocations. We develop a constitutive model incorporating DSA-assisted mobile and forest dislocation strengthening, predicting the alloy's flow behavior across a wide strain rate range. This work advances understanding of solute-dislocation interactions and unstable deformation, providing new insights for modeling DSA in engineering alloys.

动态应变时效（DSA）是许多金属合金中普遍存在的一种现象，它是由移动溶质原子和位错之间的相互作用引起的。在一定的温度和应变速率下，这些相互作用会导致超出临界应变的应变局部化，在应力-应变曲线中表现为锯齿状，即所谓的Portevin-Le ch telier （PLC）效应。虽然目前的DSA模型关注的是与溶质相互作用的边缘位错，隐含地将PLC效应归因于老化的边缘位错，但在这项工作中，我们强调了螺杆位错的关键作用。通过对al - mg - zn基交叉固溶合金在0.00005 ~ 0.1 s−1应变速率下的室温拉伸试验，我们发现DSA和应变诱导的动态析出同时控制了锯齿化行为。在低应变速率下（例如0.0001 s−1），DSA辅助沉淀在较大的菌株中导致C型锯齿，而高应变速率（例如0.1 s−1）抑制沉淀（即单一DSA），在较低的菌株中导致A型锯齿。高能x射线衍射分析表明，螺位错在早期变形中起主导作用，随着应变的增加，螺位错比例减小。透射电镜探测显示，在0.0001 s−1时，交叉滑移和塑性流动局部化受到抑制。然而，在0.1 s−1时，频繁的交叉滑移会引发早期的位错微带，并向横向扩展。这些微带内的螺旋位错驱动A型锯齿-表明它们的主要作用，而不是边缘位错。我们开发了一个包含dsa辅助移动和森林位错强化的本构模型，预测合金在宽应变速率范围内的流动行为。这项工作促进了对溶质位错相互作用和不稳定变形的理解，为工程合金中DSA的建模提供了新的见解。

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