Acta Materialia最新文献_第5页

AlCoCrFeNi2.1 eutectic high entropy alloy: defect analysis, microstructural stability and ion irradiation resilience AlCoCrFeNi2.1共晶高熵合金：缺陷分析、显微组织稳定性和离子辐照回弹性

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

Acta Materialia

Pub Date : 2026-04-01 Epub Date: 2026-02-04 DOI: 10.1016/j.actamat.2026.121985

Yuval Hodaya Malinker , Shai Salhov , Malki Pinkas , Vladimir Ezersky , Olga Girshevitz , Mauricio Sortica , Johan Oscarsson , Daniel Primetzhofer , Louisa Meshi

The AlCoCrFeNi_2.1 eutectic high entropy alloy (EHEA) features a dual-phase lamellar microstructure composed of ordered L1₂ and B2 phases, offering a unique combination of strength, ductility, and thermal stability. This study investigates the microstructural evolution, phase stability, and irradiation resilience of AlCoCrFeNi_x alloys with x = 1.9, 2.1, and 2.6. Advanced electron microscopy techniques revealed composition-dependent microstructure and confirmed the eutectic nature of the x = 2.1 alloy. Thermomechanical processing via cold rolling and annealing preserved phase ordering and enhanced mechanical properties. Irradiation of transmission electron microscopy (TEM) samples with Ne ions at doses up to 1.5 dpa enabled precise microstructure and defect analysis by comparing pre- and post-irradiation states of the same samples. The L1₂ phase exhibited dose-dependent disordering (assessed via evaluation of the fraction of 〈110〉-type dislocations), while the B2 phase retained its ordered structure, showing localized disorder and anti-phase boundaries. As a function of dose, a significant decrease in the network dislocation density (excluding dislocation loops) was observed in L1₂. On the other hand, this phase exhibited dose-dependent increase in both the density and size of dislocation loops. The B2 phase exhibited a similar effect, although the change was more moderate compared to L1₂. Semi-coherent L1₂/B2 boundaries, initially rich in dislocations, retained the Kurdjumov–Sachs orientation relationship post-irradiation, although dislocations vanished and stacking faults occasionally formed. These findings elucidate phase-specific radiation damage mechanisms and confirm the superior irradiation tolerance and structural integrity of AlCoCrFeNi_2.1, highlighting its potential for nuclear structural applications.

AlCoCrFeNi2.1共晶高熵合金（EHEA）具有由有序L1₂和B2相组成的双相层状微观结构，具有独特的强度、延展性和热稳定性。研究了x = 1.9、2.1和2.6时AlCoCrFeNix合金的显微组织演变、相稳定性和辐照回弹性。先进的电子显微镜技术揭示了x = 2.1合金的成分相关微观结构，并证实了其共晶性质。通过冷轧和退火进行热机械加工，保持了相的有序，提高了力学性能。以1.5 dpa的剂量辐照透射电子显微镜（TEM）样品，通过比较相同样品的辐照前后状态，实现了精确的微观结构和缺陷分析。L1 2相表现出剂量依赖性的无序（通过评估< 110 >型位错的分数来评估），而B2相保持其有序结构，表现出局部无序和反相边界。作为剂量的函数，在L12中观察到网络位错密度（不包括位错环）显著降低。另一方面，该相中位错环的密度和尺寸均呈剂量依赖性增加。B2期表现出类似的效果，尽管与L12期相比变化更为温和。半相干L1₂/B2边界，最初富含位错，辐照后保留了Kurdjumov-Sachs取向关系，尽管位错消失，偶尔会形成层错。这些发现阐明了相位特异性辐射损伤机制，并证实了AlCoCrFeNi2.1优越的辐照耐受性和结构完整性，突出了其在核结构应用中的潜力。

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引用次数: 0

High-entropy trace intercalation in layered semiconductors: Synergistically optimized thermoelectric performance via entropy-driven transport decoupling 层状半导体中的高熵迹嵌入：通过熵驱动的输运解耦协同优化热电性能

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

Acta Materialia

Pub Date : 2026-04-01 Epub Date: 2026-02-03 DOI: 10.1016/j.actamat.2026.121984

Hongxiang Chen , Shiyu Li , Xiaochun Wen , Jing Zhang , Bing Xiao , Yunfeng Su , Hengzhong Fan , Yongsheng Zhang

Intercalation effectively enhances the thermoelectric performance of layered semiconductors. However, conventional strategies employing a single metal element at low concentrations yield limited improvements, typically failing to achieve a zT value greater than 0.5 in intrinsic transition metal dichalcogenides (TMDCs). Here, we propose a high-entropy trace intercalation strategy by incorporating multi-component metal atoms into TiS₂. Remarkably, a high thermoelectric figure of merit (zT ≈ 0.7 at 723 K) is realized, attributed to the simultaneous optimization of thermal and electronic properties: reduced total thermal conductivity κ and high power factor (PF) with enhanced weighted mobility. Key characteristics at the optimized intercalation content (x = 0.02) include minimized lattice thermal conductivity (κ_L), sound velocity, and elastic moduli. The outstanding performance stems from entropy-engineering, where optimized intercalation (∼2%) induces a substantial entropy enhancement by 33%, generating pronounced lattice disorder and anharmonicity. Critically, this strategy avoids the increase in κ_L typically associated with higher intercalant concentrations while maintaining low effective charge doping, thereby minimizing κ. Meanwhile, favorable charge transfer from the intercalation layer to the conduction layers, along with entropy-driven band renormalization, enhances the electrical transport properties. This work establishes high-entropy trace intercalation as a universal paradigm for decoupling electronic and thermal transport in layered thermoelectrics.

嵌入有效地提高了层状半导体的热电性能。然而，采用低浓度单一金属元素的传统策略产生有限的改进，通常无法在固有过渡金属二硫族化合物（TMDCs）中实现大于0.5的zT值。在此，我们提出了一种将多组分金属原子结合到TiS2中的高熵示踪嵌入策略。值得注意的是，由于同时优化了热电性能和电子性能，实现了高热电性能（723 K时zT≈0.7）：降低了总导热系数κ和高功率因数（PF），增强了加权迁移率。优化的插层含量（x = 0.02）下的主要特征包括晶格导热系数（κL）、声速和弹性模量最小。突出的性能源于熵工程，其中优化的嵌入（~ 2%）诱导了大量的熵增强33%，产生明显的晶格无序和非调和性。关键的是，该策略避免了通常与高插层剂浓度相关的κ l的增加，同时保持低有效电荷掺杂，从而使κ最小化。同时，从插入层向导电层有利的电荷转移，以及熵驱动的能带重整化，增强了电输运性质。这项工作建立了高熵迹嵌入作为层状热电体中电子和热输运解耦的通用范例。

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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 : 2026-04-01 Epub 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

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 : 2026-04-01 Epub 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

Low Young’s modulus achieved by anelastic relaxation arising from reversible atomic shuffling in bcc Ti–Nb alloys bcc Ti-Nb合金中可逆原子变换引起的非弹性弛豫实现了低杨氏模量

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

Acta Materialia

Pub Date : 2026-04-01 Epub Date: 2026-01-27 DOI: 10.1016/j.actamat.2026.121969

Masakazu Tane , Keigo Morita , Eisuke Miyoshi , Takumi Hiramatsu

Metastable body-centered cubic (bcc) Ti alloys are attractive biomedical implant materials because they exhibit a low elastic modulus which helps mitigate bone degradation. The low elastic modulus in these alloys is believed to be correlated with a low-stability bcc structure. However, the physical nature of this correlation remains unclear. In this study, we show that the low elastic modulus of bcc Ti–Nb alloys originates from the anelastic relaxation driven by reversible atomic shuffling events that act as precursors to the

ω

(hexagonal) and

α^{''}

(orthorhombic) martensitic transformations. A combination of molecular-dynamics simulations and measurements of Young’s modulus and internal friction revealed that the reversible atomic shuffling events have a low average activation energy of 0.20 eV, leading to significant anelastic relaxation even at room temperature (

\sim

300 K), thereby lowering the elastic modulus. The reversible atomic shuffling events occur in sub-nanometer-scale, low-stability bcc regions that are depleted in the bcc-stabilizing element Nb. These regions originate from quenched-in statistical compositional fluctuations, which exist even when the constitutive elements are randomly distributed. Thus, controlling the reversible atomic shuffling events by manipulating the compositional fluctuations and the resultant local chemical composition is an effective strategy for lowering the elastic modulus of biomedical bcc Ti alloys.

亚稳体心立方（bcc）钛合金是一种极具吸引力的生物医学植入材料，因为它具有低弹性模量，有助于减轻骨降解。这些合金的低弹性模量被认为与低稳定性的bcc结构有关。然而，这种相关性的物理性质尚不清楚。在这项研究中，我们发现bcc Ti-Nb合金的低弹性模量源于可逆原子变换事件驱动的非弹性弛豫，这些事件是ω（六边形）和α”（正交）马氏体转变的前体。分子动力学模拟和杨氏模量和内摩擦测量的结合表明，可逆原子洗牌事件具有0.20 eV的低平均活化能，即使在室温（~ 300 K）下也会导致显着的非弹性弛豫，从而降低弹性模量。可逆的原子洗牌事件发生在亚纳米尺度、低稳定性的bcc区域，这些区域在bcc稳定元素Nb中被耗尽。这些区域源于淬灭的统计成分波动，即使在本构元素随机分布时也存在。因此，通过控制成分波动和由此产生的局部化学成分来控制可逆原子洗牌事件是降低生物医用bcc钛合金弹性模量的有效策略。

{"title":"Low Young’s modulus achieved by anelastic relaxation arising from reversible atomic shuffling in bcc Ti–Nb alloys","authors":"Masakazu Tane , Keigo Morita , Eisuke Miyoshi , Takumi Hiramatsu","doi":"10.1016/j.actamat.2026.121969","DOIUrl":"10.1016/j.actamat.2026.121969","url":null,"abstract":"<div><div>Metastable body-centered cubic (bcc) Ti alloys are attractive biomedical implant materials because they exhibit a low elastic modulus which helps mitigate bone degradation. The low elastic modulus in these alloys is believed to be correlated with a low-stability bcc structure. However, the physical nature of this correlation remains unclear. In this study, we show that the low elastic modulus of bcc Ti–Nb alloys originates from the anelastic relaxation driven by reversible atomic shuffling events that act as precursors to the <span><math><mi>ω</mi></math></span> (hexagonal) and <span><math><msup><mrow><mi>α</mi></mrow><mrow><mo>′</mo><mo>′</mo></mrow></msup></math></span> (orthorhombic) martensitic transformations. A combination of molecular-dynamics simulations and measurements of Young’s modulus and internal friction revealed that the reversible atomic shuffling events have a low average activation energy of 0.20 eV, leading to significant anelastic relaxation even at room temperature (<span><math><mo>∼</mo></math></span>300 K), thereby lowering the elastic modulus. The reversible atomic shuffling events occur in sub-nanometer-scale, low-stability bcc regions that are depleted in the bcc-stabilizing element Nb. These regions originate from quenched-in statistical compositional fluctuations, which exist even when the constitutive elements are randomly distributed. Thus, controlling the reversible atomic shuffling events by manipulating the compositional fluctuations and the resultant local chemical composition is an effective strategy for lowering the elastic modulus of biomedical bcc Ti alloys.</div></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":"307 ","pages":"Article 121969"},"PeriodicalIF":9.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

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 : 2026-04-01 Epub 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

Field-driven magnetization processes, magnetocalloric effect and tunneling magnetoconductivity in bilayer CrI3 thin films: Insights from replica-exchange Monte Carlo simulations 场驱动磁化过程、磁热效应和双层cri3薄膜的隧道导电性：来自复制交换蒙特卡罗模拟的见解

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

Acta Materialia

Pub Date : 2026-04-01 Epub Date: 2026-02-02 DOI: 10.1016/j.actamat.2026.121975

Phong H. Nguyen , Cong T. Bach , Huy D. Nguyen , Hoai T.L. Nguyen , Hanh H. Mai , Duy Q. Dao , Giang H. Bach

We employ replica-exchange Monte Carlo simulations of Ising model for a bilayer honeycomb spin lattice with

S = 3 / 2

to investigate field-driven magnetic behavior and first-order magnetization processes (FOMPs). The simulations reveal a step-like field dependence of the magnetic moment at low temperatures with a sudden saturation, occurring at a critical field

h_{c}

that linearly varies with interlayer coupling

J_{z}

. Without a magnetic field, an interlayer antiferromagnetic alignment is confirmed below the Néel temperature

T_{N}

for arbitrary interlayer coupling

J_{z}

, with

T_{N}

decreasing as the interlayer coupling strength

| J_{z} |

weakens. We further analyzed the temperature dependence of layer-resolved magnetic moments, thermodynamic quantities and their relations to the magneto-caloric effect, where the magnetic entropy change

- Δ S_{M}

exhibits a double-peak structure in systems with competing AFM and FM interactions. Finally, we calculate the field dependence of the relative magnetoconductivity and compare it with experimental measurements, clarifying the intimate relationship between FOMPs and tunneling magnetoconductivity in bilayer CrI

_{3}

thin films.

本文采用复制交换蒙特卡罗模拟了S=3/2双层蜂窝自旋晶格的Ising模型，研究了场驱动磁行为和一阶磁化过程（FOMPs）。模拟结果表明，在低温下，磁矩随层间耦合Jz线性变化的临界场hc出现突然饱和，磁矩的场依赖性呈阶梯状。在没有磁场的情况下，任意层间耦合Jz在n温度TN以下存在层间反铁磁取向，且随着层间耦合强度|Jz|的减弱，TN逐渐减小。我们进一步分析了层分辨磁矩、热力学量的温度依赖性及其与磁热效应的关系，其中磁熵变化- ΔSM在具有相互竞争的AFM和FM相互作用的系统中呈现双峰结构。最后，我们计算了相对磁导率的场依赖性，并将其与实验测量结果进行了比较，阐明了双层CrI3薄膜中FOMPs与隧道磁导率之间的密切关系。

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引用次数: 0

Cross-Plane Thermal Transport in Columnar-grained Films Governed by Coordinated Evolution of Grain Size and Edge Dislocation Distribution 晶粒尺寸和边缘位错分布的协调演化控制柱状晶膜的平面热输运

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

Acta Materialia

Pub Date : 2026-03-24 DOI: 10.1016/j.actamat.2026.122158

Mingquan Jiang, Mai Yang, Bingqi Linghu, Shichen Lv, Donghao Li, Liangliang Lin, Jie Zhu, Qingfang Xu, Rong Tu, Dawei Tang, Song Zhang, Lianmeng Zhang

The increase in cross-plane thermal conductivity (κ_⊥) of columnar-grained films with film growth is commonly attributed to grain size constraints on phonon mean free paths (MFPs). However, idealized assumptions about grain growth in previous studies have failed to accurately elucidate the evolution of grain size-induced suppression of thermal transport during film growth. Furthermore, the impact of evolving edge dislocation distributions accompanying grain growth on thermal transport is also frequently overlooked. Therefore, the mechanisms governing cross-plane thermal transport in columnar-grained films are investigated in this study from the perspective of coordinated evolutions of grain size and edge dislocation distribution, based on TiSiN films. The results indicate that the grain morphology evolves from a conical to a columnar microstructure as the film growth undergoes three stages of nucleation, competitive growth, and columnar growth, accompanied by the evolution of dislocation distributions from high-density networked aggregates in bottom conical grains to low-density linear arrays in top columnar grains. This coordinated evolution leads to alternating dominance of grain boundary and dislocation scattering of heat-carrying phonons across growth stages, ultimately causing κ_⊥ to increase with film growth.

柱状颗粒膜的跨平面导热系数（κ⊥）随着膜的生长而增加，通常归因于声子平均自由程（MFPs）的晶粒尺寸限制。然而，以往研究中对晶粒生长的理想化假设，并不能准确解释薄膜生长过程中晶粒尺寸对热输运抑制的演化过程。此外，随着晶粒生长而变化的边缘位错分布对热输运的影响也经常被忽视。因此，本研究基于TiSiN薄膜，从晶粒尺寸和边缘位错分布的协调演变角度研究柱状晶膜中跨平面热输运的机制。结果表明：薄膜生长经历成核、竞争生长和柱状生长三个阶段，晶粒形貌由锥形向柱状组织演变，同时位错分布由底部锥形晶粒高密度网状聚集向顶部柱状晶粒低密度线性排列演变。这种协调的演化导致晶界的交替优势和携带热量的声子在生长阶段的位错散射，最终导致κ⊥随着薄膜的生长而增加。

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引用次数: 0

A Novel Theoretical Framework for Predicting Heteroepitaxial Film Growth Modes 预测异质外延薄膜生长模式的新理论框架

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

Acta Materialia

Pub Date : 2026-03-24 DOI: 10.1016/j.actamat.2026.122150

Dong Yang, Li Sheng

Exploring the epitaxial growth mode of film on heterogeneous substrates is highly significant for the integration of materials with different properties into a single device, leading to improved performance and functionality. We develop a widely applicable thermodynamic framework for predicting the epitaxial growth mode of film. Especially, this framework is validated by the investigation into the epitaxial growth mode and underlying mechanisms of AlN on Al₂O₃ substrate. Analysis confirms that AlN with aluminum polarity constitutes the dominant configuration on Al₂O₃ substrates. Moreover, a clear transition from the Frank-van der Merwe (FV) mode to the Stranski-Krastanow (SK) mode and eventually to the Volmer-Weber (VW) mode is revealed during AlN growth. Crucially, we demonstrate that mitigating strain energy accumulation—resulting from lattice mismatch—is essential for achieving high-quality epitaxial AlN thin films on Al₂O₃ substrates, which can be effectively achieved by introducing a buffer layer between the film and the substrate. The theoretical framework presented in this paper provides a unified mechanism for understanding growth mode evolution on heterogeneous substrates and offers foundational principles for guiding epitaxial experimental design.

探索异质衬底上薄膜的外延生长模式对于将不同性质的材料集成到单个器件中，从而提高性能和功能具有重要意义。我们开发了一个广泛适用的热力学框架来预测薄膜的外延生长模式。特别是，通过对AlN在Al2O3衬底上的外延生长方式和潜在机制的研究，验证了这一框架。分析证实，具有铝极性的AlN在Al2O3衬底上占主导地位。此外，在AlN的生长过程中，揭示了从Frank-van der Merwe （FV）模式到Stranski-Krastanow （SK）模式，最终到Volmer-Weber （VW）模式的明显转变。至关重要的是，我们证明了减轻由晶格错配引起的应变能积累对于在Al2O3衬底上获得高质量的外延AlN薄膜是必不可少的，这可以通过在薄膜和衬底之间引入缓冲层来有效地实现。本文提出的理论框架为理解异质衬底上生长模式演化提供了统一的机制，并为指导外延实验设计提供了基本原则。

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引用次数: 0

Scaling kinetic Monte-Carlo simulations of grain growth with combined convolutional and graph neural networks 结合卷积神经网络和图神经网络的晶粒生长动力学蒙特卡罗模拟

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

Acta Materialia

Pub Date : 2026-03-23 DOI: 10.1016/j.actamat.2026.122153

Zhihui Tian, Ethan Suwandi, Tomas Oppelstrup, Vasily V. Bulatov, Joel B. Harley, Fei Zhou

引用次数: 0