Acta Materialia最新文献_第4页

Simultaneous enhancement of mechanical and thermoelectric properties via precipitation engineering in Mg3(Sb, Bi)2 沉淀法同时增强Mg3(Sb, Bi)2的力学和热电性能

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

Acta Materialia

Pub Date : 2026-01-24 DOI: 10.1016/j.actamat.2026.121958

Peng Xie , Lifeng Jiang , Shuyue Tan , Hongda Song , Xinghui Wang , Jingyi Xiao , Huijun Kang , Zongning Chen , Enyu Guo , Jun Wang , Tongmin Wang

Precipitation strengthening is a well-established mechanism for enhancing mechanical properties in metals. As for thermoelectric materials, however, research on precipitates has primarily focused on their role in decoupling electron and phonon transport, with their potential for improving mechanical properties receiving limited attention. Herein, we systematically investigate the synergistic effects of V-rich nanoscale precipitates on both the thermoelectric and mechanical properties of Mg₃(Sb, Bi)₂. These precipitates promote grain growth and donate electrons to the matrix, leading to a high electrical conductivity of 6.3 × 10⁴ S·m^-1 at 323 K. Their uniform dispersion also effectively enhances phonon scattering, yielding an average figure of merit (zT) of 1.2 over 323-723 K. More importantly, we discover that deformation triggers dynamic precipitation in polycrystalline Mg₃(Sb, Bi)₂. Applied stress generates a high density of dislocations and sub-grain boundaries, which serve as fast diffusion pathways facilitating the reprecipitation of Mg-rich and Bi-rich phases, thereby simultaneously strengthening and toughening the material. Consequently, the optimized Mg_3.19V_0.01Sb_1.5Bi_0.49Te_0.01 demonstrates a compressive strain of 47 % together with a compressive strength of 550 MPa. This work elucidates the dual role of nano-precipitates in governing both thermoelectric transport and mechanical reliability, offering new insights and an effective strategy for strengthening Mg₃(Sb, Bi)₂-based thermoelectrics.

沉淀强化是一种公认的提高金属力学性能的机制。然而，对于热电材料，沉淀物的研究主要集中在它们在电子和声子输运中的去耦作用上，它们改善机械性能的潜力受到的关注有限。本文系统地研究了富v纳米级析出物对Mg3(Sb, Bi)2热电性能和力学性能的协同效应。这些析出相促进晶粒生长并向基体提供电子，导致在323 K时的高电导率为6.3 × 104 S·m-1。它们的均匀色散也有效地增强了声子散射，在323-723 K上的平均性能值（zT）为1.2。更重要的是，我们发现变形触发了多晶Mg3(Sb, Bi)2的动态析出。外加应力产生了高密度的位错和亚晶界，它们作为快速扩散途径促进了富mg和富bi相的再析出，从而同时增强和增韧材料。因此，优化后的Mg3.19V0.01Sb1.5Bi0.49Te0.01的压缩应变为47%，抗压强度为550 MPa。这项工作阐明了纳米沉淀物在控制热电输运和机械可靠性方面的双重作用，为强化Mg3(Sb, Bi)2基热电材料提供了新的见解和有效的策略。

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引用次数: 0

Controlling interface atomic structure and distribution of oxide particles for improved ductility in Mo alloys 控制界面原子结构和氧化物颗粒分布以提高Mo合金的延展性

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

Acta Materialia

Pub Date : 2026-01-23 DOI: 10.1016/j.actamat.2026.121961

Z. Dong, M. Wang, M.X. Huang

Achieving a synergistic balance between strength and ductility remains a longstanding challenge for molybdenum (Mo) alloys. In this study, we systematically investigate three Mo alloys reinforced with different oxide particles (Y₂O₃, CeO₂, and (Ce,Y)_xO_y), all exhibiting comparable yield strengths. The Mo-Y₂O₃ alloy contains disordered, incoherent Y₂O₃/Mo interfaces that generate severe local stress concentrations and premature interface decohesion, resulting in negligible uniform elongation. In contrast, the Mo-CeO₂ alloy features semi-coherent CeO₂(200)//Mo(101) interfaces that enhance dislocation storage capacity and yield a uniform elongation of 6.3%. Remarkably, the co-addition of CeO₂ and Y₂O₃ produces novel (Ce,Y)_xO_y particles, with a y/x ratio of approximately 1.7, that exhibit a CeO₂

(11 \overline{1})

//Mo(200) incoherent interface. This tailored interface permits dislocation glide with moderate resistance, enabling sustained dislocation accumulation without severely restricting mobility. Furthermore, the Mo-CeO₂-Y₂O₃ alloy exhibits an optimized oxide distribution, promoting a homogeneous and fully recrystallized microstructure, thereby mitigating intergranular fracture and further improving ductility. As a result, the Mo-CeO₂-Y₂O₃ alloy achieves uniform and total elongations of 11.8% and 33%, respectively, nearly double those of the Mo-CeO₂ alloy and far exceeding those of the Mo-Y₂O₃ alloy. Our research highlights the pivotal role of strategic oxide design in controlling interface atomic structure, oxide distribution, and grain microstructure in Mo alloys, offering a promising pathway to strong and ductile oxide dispersion-strengthened metals.

实现强度和延展性之间的协同平衡仍然是钼（Mo）合金长期面临的挑战。在这项研究中，我们系统地研究了三种不同氧化物颗粒（Y2O3， CeO2和（Ce，Y）xOy）增强的Mo合金，它们都具有相当的屈服强度。Mo-Y2O3合金含有无序的、不一致的Y2O3/Mo界面，产生严重的局部应力集中和过早的界面脱粘，导致可忽略的均匀伸长率。相比之下，Mo-CeO2合金具有半共格的CeO2(200)//Mo（101）界面，提高了位错储存能力，并获得了6.3%的均匀伸长率。值得注意的是，CeO2和Y2O3的共加入产生了新的（Ce，Y）xOy粒子，其Y /x比约为1.7，表现出CeO2(111)//Mo（200）不相干界面。这种定制的界面允许位错以适度的阻力滑动，从而实现持续的位错积累，而不会严重限制活动能力。此外，Mo-CeO2-Y2O3合金表现出优化的氧化物分布，促进了均匀和完全再结晶的组织，从而减轻了晶间断裂，进一步提高了延展性。结果表明，Mo-CeO2- y2o3合金的均匀伸长率和总伸长率分别为11.8%和33%，是Mo-CeO2合金的近两倍，远远超过Mo-Y2O3合金。我们的研究强调了战略氧化物设计在控制Mo合金界面原子结构、氧化物分布和晶粒微观结构方面的关键作用，为制备强韧性氧化物弥散增强金属提供了一条有希望的途径。

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引用次数: 0

Insights into the preferential intergranular oxidation mechanism of 316L austenitic stainless steel exposed to oxygen saturated lead-bismuth eutectic (LBE) 饱和氧铅铋共晶（LBE）下316L奥氏体不锈钢晶间优先氧化机制的研究

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

Acta Materialia

Pub Date : 2026-01-23 DOI: 10.1016/j.actamat.2026.121962

Wenhao Zhang , Wen Wang , Jibo Tan , Xing Gong , En-Hou Han , Wenjun Kuang

The preferential intergranular oxidation (PIO) behavior of 316L stainless steel (SS) exposed to oxygen saturated Lead-bismuth eutectic (LBE) at 550 °C was investigated. PIO occurred at both random high angle grain boundaries (RHABs) and coherent twin boundaries (CTBs), with RHABs exhibiting deeper intergranular oxidation. The high diffusivity of RHAB supports rapid diffusion of Cr toward the PIO front, leading to the formation of extensive polycrystalline Cr₂O₃. In contrast, only a thin flake of Cr₂O₃ was observed at the oxidation front of CTB. Diffusion induced grain boundary migration (DIGM) zones were observed not only at RHAB oxidation front, but also at CTB front. Driven by Ni dissolution through intergranular pores, the DIGM zone further degrades into fragmented Ni-enriched particles along RHAB. Nano-pores, formed via Ni selective leaching and Fe outward diffusion, were observed in intergranular oxides at the oxidation fronts of both RHAB and CTB. These intergranular pores constitute rapid diffusion paths, significantly aggravating PIO.

研究了316L不锈钢（SS）在550℃饱和氧铅铋共晶（LBE）下的优先晶间氧化（PIO）行为。PIO发生在随机高角晶界（RHABs）和相干孪晶界（CTBs），其中RHABs表现出更深的晶间氧化。RHAB的高扩散率支持Cr向PIO前沿快速扩散，导致形成广泛的Cr2O3多晶。相比之下，在CTB的氧化前沿只观察到一层薄薄的Cr2O3。扩散诱导晶界迁移（DIGM）区不仅存在于RHAB氧化锋，也存在于CTB氧化锋。在Ni通过晶间孔隙溶解的驱动下，DIGM区沿RHAB进一步降解为破碎的富Ni颗粒。在RHAB和CTB氧化前沿的晶间氧化物中均观察到Ni选择性浸出和Fe向外扩散形成的纳米孔。这些粒间孔隙构成快速扩散路径，显著加重PIO。

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引用次数: 0

Architecting Ta-V-enriched local chemical ordering for strength-ductility synergy in multi-principal element alloys 构建富含ta - v的多主元素合金强度-延性协同局部化学排序

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

Acta Materialia

Pub Date : 2026-01-23 DOI: 10.1016/j.actamat.2026.121960

Zheng Li , Zhichao Meng , Dingxin Liu , Chang Liu , Xiaowei Zuo

Local chemical ordering (LCO) is a key microstructural feature in multi-principal element alloys (MPEAs), critically influencing their mechanical properties. However, the mechanisms of LCO formation and their interactions with dislocations remain unclear, and effective strategies for architecting LCOs to enhance both strength and ductility are lacking. In this work, we achieve controlled formation of novel Ta-V-enriched LCOs within a Ti-Zr-Nb-Ta-V alloy system, and investigate their formation mechanisms and interactions with dislocations through a combination of experimental characterization, thermodynamic calculations, and molecular dynamics simulations. Our results reveal that these LCOs, which act as precursors to the C15 Laves phase, exhibit two distinct morphologies: string-like and cluster-like, whose prevalence depends on V content. Mobile dislocations interact with string-like and cluster-like LCOs via shearing and bypassing mechanisms, respectively. Cluster-like LCOs provide stronger and more sustainable barriers to dislocation motion than their string-like counterparts. Importantly, they not only strengthen the matrix by impeding dislocation motion but also enhance ductility by promoting dislocation multiplication and activating multiple slip systems. Dislocation loops generated by interactions with cluster-like LCOs act as Frank-Read sources, expanding during deformation to facilitate further activity. Consequently, the V15 alloy, rich in cluster-like LCOs, exhibits synergistic mechanical improvements over the V5 alloy, achieving a yield strength of 1.04 GPa, ultimate tensile strength of 1.2 GPa, and ductility of 20.6 %. This work provides fundamental insights into LCO-driven deformation mechanisms and opens a pathway for designing high-performance MPEAs through precise LCO control.

局部化学有序（LCO）是多主元素合金（mpea）的关键组织特征，对合金的力学性能有重要影响。然而，LCO的形成机制及其与位错的相互作用仍不清楚，并且缺乏有效的LCO构建策略来提高强度和延性。在这项工作中，我们在Ti-Zr-Nb-Ta-V合金体系中实现了新型富含ta - v的LCOs的可控形成，并通过实验表征、热力学计算和分子动力学模拟相结合，研究了它们的形成机制以及与位错的相互作用。我们的研究结果表明，这些LCOs作为C15 Laves相的前体，表现出两种不同的形态：弦状和簇状，其流行程度取决于V的含量。移动位错分别通过剪切和旁路机制与柱状和簇状lco相互作用。簇状lco比弦状lco提供更强、更可持续的位错运动障碍。重要的是，它们不仅通过阻碍位错运动来增强基体，而且通过促进位错增殖和激活多滑移系统来增强基体的延展性。与簇状lco相互作用产生的位错环作为弗兰克-里德源，在变形过程中扩大，以促进进一步的活动。结果表明，与V5合金相比，富含团簇状lco的V15合金表现出协同力学性能的改善，屈服强度为1.04 GPa，极限抗拉强度为1.2 GPa，延展性为20.6%。这项工作为LCO驱动的变形机制提供了基本的见解，并为通过精确的LCO控制设计高性能mpea开辟了途径。

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引用次数: 0

Lamellar architecture and resultant two-way memory mechanism in NiTi alloy by magnetic field-assisted additive manufacturing 磁场辅助增材制造NiTi合金片层结构及其双向记忆机制

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

Acta Materialia

Pub Date : 2026-01-23 DOI: 10.1016/j.actamat.2026.121963

Weisi Cai , Hongwei Ma , Tao Chen , Pengxu Li , Sizhan Liu , Changhui Song , Xiaoqiang Li , Chao Yang

Additive manufacturing (AM) enables transformative design freedom for metallic components, while field-assisted AM provides an expanded space for microstructure control. Herein, we report on magnetic field-assisted laser powder bed fusion of NiTi shape memory alloys, which can introduce unprecedented lamellar architecture and enhance two-way shape memory effect (TWSME). By coupling unidirectional scanning strategy with 50 mT vertical static magnetic field, NiTi specimen (MS) exhibits a directional lamellar architecture (widths ∼185 μm) comprising alternating B19′ martensite and B2 austenite. Fundamentally, the lamellae originate from thermoelectric magnetohydrodynamic effects: Lorentz forces arising from the interaction between thermoelectric currents and the applied magnetic field induce a melt pool deflection of approximately 33.6°. This deflection converts the austenite and martensite regions from a disordered alternation into a well-ordered lamellar architecture. After identical thermomechanical training, the specimen MS exhibits far higher TWSME strains (0.97 % for compression and 0.75 % for tension) than the corresponding ones for the counterpart without magnetic field assistance. Microstructural analysis reveals that the lamellar architecture facilitates directional internal stress fields, enabling alternating favored correspondence variant pair (CVP) zones and strain accommodation zones. The favored CVP zones enhance recoverable strain, while the strain accommodation zones alleviate the lattice incompatibility, collectively contributing to the superior TWSME. This work provides fundamental insights into field-assisted microstructure tailoring and performance enhancement in AM.

增材制造（AM）实现了金属部件的变革性设计自由，而现场辅助AM为微观结构控制提供了扩展的空间。本文报道了磁场辅助激光粉末床熔合NiTi形状记忆合金，该方法可以引入前所未有的片层结构并增强双向形状记忆效应（TWSME）。通过将单向扫描策略与50 mT垂直静磁场耦合，NiTi试样（MS）呈现出由B19′马氏体和B2奥氏体交替组成的定向片层结构（宽度约185 μm）。从根本上说，片层源于热电磁流体动力学效应：由热电电流和外加磁场之间的相互作用产生的洛伦兹力导致熔池偏转约33.6°。这种偏转使奥氏体和马氏体区域从无序交替转变为有序的片层结构。经过相同的热机械训练后，样品MS显示的TWSME应变（压缩时为0.97%，拉伸时为0.75%）远高于没有磁场辅助的样品。微观结构分析表明，层状结构有利于内部应力场的定向，形成交替的有利对应变对（CVP）区和应变调节区。有利的CVP区增加了可恢复应变，而应变调节区减轻了晶格不相容，共同导致了优越的TWSME。这项工作为现场辅助微结构定制和增材制造性能增强提供了基本见解。

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引用次数: 0

In-situ phase transition in P3-type layered oxide for high-performance Na-ion cathode 高性能钠离子阴极用p3型层状氧化物原位相变研究

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

Acta Materialia

Pub Date : 2026-01-22 DOI: 10.1016/j.actamat.2026.121955

Wenhui Li, Yang Jiang, Kun Luo

P-type layered oxide materials have mesmerized great attention in view of higher security and lower price. Unfortunately, intrinsic Na⁺/vacancy ordering reorganization and deleterious structural evolution are observed in P-type materials during electrochemical processes, resulting in stepwise electrochemical profiles along with rapid capacity attenuation and poor rate capability. P3-type layered cathode material with medium-entropy cation arrangement, P3-Na_0.75[Mg_0.05Al_0.05Zn_0.08Ni_0.22Mn_0.6]O₂ (MEO), is devised and manufactured in this manuscript. The material represents smooth electrochemical profiles without apparent voltage plateaus ranging from 2.0 V to 4.5 V, revealing a specific capacity of 115 mAh g^-1. Through structural characterizations, it has been demonstrated that MEO undergoes complete solid-solution reactions throughout the entire voltage range, promoting rapid diffusion of Na⁺ ions during the reaction (10^–10 cm² s^-1). As the charging reaches to high voltage, the material undergoes an in-situ phase transformation from P3 phase to “Z” phase which is identified as an intergrowth of P-type stacking to O-type stacking. The MEO material represents outstanding electrochemical behaviors with high rate capability (∼80 mAh g^-1 at 5 C, 1 C = 150 mA g^-1) and an ultra-long cycling life (2000 cycles). In addition, the material can work properly over a varied temperature range (85 mAh g^-1 at -45 °C and 126 mAh g^-1 at 50 °C). The conclusions reported in this manuscript prove a beneficial method to suppress the complex stepwise electrochemical curves caused by the sudden P-O phase transformation in P3-type oxide cathode materials via the in-situ phase transition in order to realize outstanding electrochemical behaviors.

p型层状氧化物材料以其较高的安全性和较低的价格而备受关注。然而，p型材料在电化学过程中存在固有的Na+/空位有序重组和有害的结构演化，导致其电化学分布呈阶梯状，容量衰减快，速率性能差。本文设计并制备了中熵阳离子排列的p3型层状正极材料P3-Na0.75[Mg0.05Al0.05Zn0.08Ni0.22Mn0.6]O2 （MEO）。该材料具有光滑的电化学曲线，在2.0 V至4.5 V范围内没有明显的电压平台，显示出115 mAh g-1的比容量。通过结构表征，证明了MEO在整个电压范围内发生完整的固溶反应，促进了Na+离子在反应过程中的快速扩散（10-10 cm2 s-1）。当充电达到高电压时，材料发生原位相变，由P3相转变为Z相，这是p型堆叠向o型堆叠的共同生长。MEO材料具有优异的电化学性能，具有高倍率性能（在5℃时约80 mAh g-1, 1℃= 150 mA g-1）和超长循环寿命（2000次循环）。此外，该材料可以在不同的温度范围内正常工作（-45°C时85 mAh g-1, 50°C时126 mAh g-1）。本文的结论证明了通过原位相变来抑制p3型氧化物正极材料中P-O相变引起的复杂的逐步电化学曲线，从而实现优异的电化学性能的有益方法。

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引用次数: 0

Structural origins of thermal expansion behavior in 2D materials 二维材料热膨胀行为的结构根源

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

Acta Materialia

Pub Date : 2026-01-22 DOI: 10.1016/j.actamat.2026.121956

Yang Yang , Guangya Li , Yixin Lin , Yan Chen , Hongxiang Zong , Xiangdong Ding , Xun-Li Wang , Jun Sun

Two-dimensional (2D) materials exhibit diverse thermal expansion behavior—with coefficients spanning a broad range from negative to positive values—fundamentally challenging our understanding of thermal expansion mechanisms and creating critical uncertainties in thermal stress prediction for next-generation devices. Despite numerous experimental measurements, the fundamental structural mechanisms underlying this remarkable variability remains elusive. Here, we resolve this longstanding puzzle through systematical molecular dynamics simulations of four representative 2D materials: hBN, PbTe, graphene, and MoS₂. Our simulations reveal that thermal expansion behavior is governed by the interplay between the intrinsic chemical bond thermal expansion and out-of-plane structural flexibility. This interplay enables 2D materials to achieve thermal expansion coefficients ranging from -15.0 × 10⁻⁶ K⁻¹ to +52.4 × 10⁻⁶ K⁻¹. Crucially, we demonstrate that thickness and lateral size effects arise exclusively through modulation of out-of-plane deformation freedom, while substrate interactions operate via a dual pathway that simultaneously constrains structural flexibility and modifies intrinsic bond behavior. Our findings culminate in a universal scaling relationship between area-specific bending rigidity and thermal expansion coefficients, providing the first predictive framework for 2D material thermal behavior.

二维（2D）材料表现出不同的热膨胀行为-系数跨越从负值到正值的广泛范围-从根本上挑战了我们对热膨胀机制的理解，并在下一代设备的热应力预测中产生了关键的不确定性。尽管进行了大量的实验测量，但这种显著变化背后的基本结构机制仍然难以捉摸。在这里，我们通过系统的分子动力学模拟四种代表性的二维材料：hBN， PbTe，石墨烯和MoS 2来解决这个长期存在的难题。我们的模拟表明，热膨胀行为是由固有化学键热膨胀和面外结构柔性之间的相互作用所控制的。这种相互作用使二维材料的热膨胀系数从-15.0 × 10⁻⁶K⁻¹到+52.4 × 10⁻⁶K⁻¹。至关重要的是，我们证明了厚度和横向尺寸效应仅通过调制面外变形自由产生，而基材相互作用通过双重途径同时限制结构灵活性和改变固有键行为。我们的研究结果最终得出了区域特定弯曲刚度和热膨胀系数之间的普遍标度关系，为二维材料热行为提供了第一个预测框架。

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引用次数: 0

Interstitial nitrogen-engineered square-planar Ni surfaces enabling efficient hydrogenation 间隙氮工程的方形平面Ni表面实现高效氢化

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

Acta Materialia

Pub Date : 2026-01-22 DOI: 10.1016/j.actamat.2026.121954

Yinghui Pu , Yiming Niu , Tongtong Gao , Junnan Chen , Bingsen Zhang

Atomically precise engineering of nanocatalyst surfaces is critical for advancing heterogeneous catalysis, yet achieving both structural uniformity and electronic tunability remains challenging. Here, we report an interstitial atom-mediated strategy for constructing anti-perovskite Ni₃CuN nanocatalysts featuring square-planar Ni surfaces coordinated by nitrogen. The resulting nanoparticles adopt cubic morphologies, undergoing nitrogen-driven facet reconstruction from high-index {210}/{110} planes to thermodynamically favored {100} facets. Atomic-resolution imaging and simulations reveal that these surfaces preferentially expose Ni-N arrangements on (

\bar{1}

00) terminations, in contrast to Ni-Cu configurations on (100) facets. This well-defined surface architecture, characterized by expanded Ni-Ni distances and electron-deficient Ni sites, leads to a substantial enhancement in acetylene hydrogenation selectivity (from 25.5% to 80.1%), while maintaining or surpassing the intrinsic activity of pure Ni and exhibiting excellent stability over 110 h of testing. These findings establish an interstitial atom-based strategy for tailoring catalytic nanostructures with precise control over surface geometry and electronic structure.

纳米催化剂表面的原子精确工程对于推进多相催化至关重要，但实现结构均匀性和电子可调性仍然具有挑战性。在这里，我们报道了一种间隙原子介导的策略，用于构建具有方形平面Ni表面和氮配位的反钙钛矿Ni3CuN纳米催化剂。所得纳米颗粒采用立方形态，经过氮驱动的面重构，从高折射率{210}/{110}平面到热力学有利的{100}面。原子分辨率成像和模拟显示，与（100）面上的Ni-Cu配置相比，这些表面优先暴露（1¯00）端部的Ni-N排列。这种明确的表面结构，以扩大Ni-Ni距离和缺乏电子的Ni位点为特征，导致乙炔加氢选择性大幅提高（从25.5%提高到80.1%），同时保持或超过纯Ni的固有活性，并在110小时的测试中表现出优异的稳定性。这些发现建立了一种基于间隙原子的策略，可以通过精确控制表面几何形状和电子结构来定制催化纳米结构。

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引用次数: 0

Direct measurement of the Gibbs free energy of mixing via atom probe tomography 用原子探针层析成像直接测量混合的吉布斯自由能

IF 9.4 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Acta Materialia

Pub Date : 2026-01-22 DOI: 10.1016/j.actamat.2026.121950

Jianshu Zheng, Rüya Duran, Parisha Diwan, Guido Schmitz, Sebastian M. Eich

The concept of thermodynamic free energy plays a central role across various disciplines, providing critical insights into system dynamics, energy flow, and sustainability. In materials science, Gibbs free energies are typically determined through phase diagram modeling, which relies on a broad range of thermodynamic data. This process requires the investigation of well-equilibrated materials, a task that can be time-consuming or even impractical for systems with low mobility. In this study, we introduce a novel methodology for extracting the composition dependence of the Gibbs free energy of mixing from local composition fluctuations in solids using atom probe tomography (APT). We present both the theoretical framework and practical implementation through computational simulations, as well as experimental validation using APT data from Cu–Ni alloys. The experimental phase diagram constructed from the resulting Gibbs free energy of mixing shows excellent agreement with CALPHAD-based predictions. This approach provides superior accuracy and efficiency, as equilibration on the nanometer scale can be achieved in a relatively short time. It holds promising potential for application to multi-component solids, liquids, and organic systems, particularly with emerging techniques like cryo-APT.

热力学自由能的概念在各个学科中发挥着核心作用，为系统动力学、能量流和可持续性提供了关键的见解。在材料科学中，吉布斯自由能通常是通过相图建模来确定的，这依赖于广泛的热力学数据。这一过程需要对平衡良好的材料进行研究，对于低迁移率的系统来说，这是一项耗时甚至不切实际的任务。在这项研究中，我们引入了一种新的方法，利用原子探针断层扫描（APT）从固体的局部成分波动中提取混合吉布斯自由能的成分依赖性。我们通过计算模拟提出了理论框架和实际实现，并利用Cu-Ni合金的APT数据进行了实验验证。由得到的混合吉布斯自由能构建的实验相图与基于calphad的预测结果非常吻合。这种方法提供了优越的精度和效率，因为在纳米尺度上的平衡可以在相对较短的时间内实现。它在多组分固体、液体和有机系统中具有广阔的应用前景，特别是与cryo-APT等新兴技术相结合。

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引用次数: 0

Multi-block element modulation enables high temperature superconductivity in quaternary hydrides at low pressures 多块元件调制使低温下的季氢化物具有高温超导性

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

Acta Materialia

Pub Date : 2026-01-21 DOI: 10.1016/j.actamat.2026.121953

Pengye Liu , Mingyang Du , Tian Cui , Zhao Liu

Hydrides synthesis guided by structural design has significantly advanced the exploration for high-temperature superconductors but most hydrides still require extremely high pressures, which hinders their practical applications. Here, we propose a design strategy based on alloyed A15 frameworks, guided by chemical bonding principles and the strategic tuning of elements from different blocks of the periodic table, through which a series of superconducting quaternary XYZ₂H₁₂ hydrides were constructed. First-principles calculations identified six thermodynamically stable hydrides out of 80 candidates at 20 GPa, with GaAlZr₂H₁₂ and GaAlHf₂H₁₂ exhibiting T_c of 74 K and 69 K, respectively. Notably, the T_c of GaAlZr₂H₁₂ increases to 79 K at 15 GPa, exceeding the temperature of liquid nitrogen. Importantly, we reveal that the incorporation of p- and d-block elements enhances the density of states at the Fermi level and induces phonon softening via Fermi surface nesting, thereby significantly enhancing electron-phonon coupling strength. And strong electron-phonon matrix elements, primarily driven by hydrogen vibrations, significantly contribute to boost superconductivity in GaAlZr₂H₁₂ and GaAlHf₂H₁₂. Our study demonstrates that the bonding-guided approach combined with multiblock elemental tuning strategy offers an effective route for designing stable hydride superconductors, while providing guidance for realizing high-T_c superconductor under experimentally accessible low pressures.

以结构设计为指导的氢化物合成极大地推进了对高温超导体的探索，但大多数氢化物仍然需要极高的压力，这阻碍了它们的实际应用。在此，我们提出了一种基于合金A15框架的设计策略，以化学键原理和元素周期表不同区块元素的策略调整为指导，通过该策略构建了一系列超导XYZ2H12四元氢化物。第一性原理计算确定了80种候选氢化物中的6种，其中GaAlZr2H12和GaAlHf2H12的Tc分别为74 K和69 K。值得注意的是，在15 GPa时，GaAlZr2H12的Tc升高到79 K，超过了液氮温度。重要的是，我们揭示了p和d块元素的结合增强了费米能级的态密度，并通过费米表面嵌套诱导声子软化，从而显著增强了电子-声子耦合强度。由氢振动驱动的强电子-声子矩阵元素对GaAlZr2H12和GaAlHf2H12的超导性有显著的促进作用。我们的研究表明，结合多块元素调谐策略的键导方法为设计稳定的氢化物超导体提供了有效的途径，同时为在实验可及的低压下实现高tc超导体提供了指导。

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