Materialia最新文献_第4页

A strategy for reducing yield-to-tensile ratio in HSLA steel: induced elemental partitioning to promote reverse austenite formation 降低HSLA钢屈服拉伸比的策略：诱导元素分配促进反向奥氏体形成

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.mtla.2025.102642

Borui Ren , Ye Cui , Tenglong Gong , Xiyuan Xiao , Lixin Sun , Yang Zhang , Yuxin Wu , Tan Zhao , Gang Zhao , Zhongwu Zhang

High-strength low-alloy (HSLA) steels have emerged as a candidate material in engineering applications, attributed to their balanced strength, good plasticity, and favorable weldability. However, stabilizing film-like reverse austenite (RA) at room temperature is difficult due to low alloy content of HSLA steels, which becomes a challenge to prevent the concurrent achievement of high elongation and a low yield-to-tensile ratio. In this study, a martensite-based microstructure featuring stable film-like RA and uniformly distributed Cu-rich nanoprecipitates is successfully produced in a low-alloy steel through a process involving quenching, cold rolling with 2% deformation, lamellarization, and tempering. The results reveal that 2% deformation induces dislocations, which effectively control fresh martensite (FM) with higher length-to-diameter (L/D) ratio and an initial Ni enrichment of 4.67%. Additionally, the partitioning of Ni elements during tempering creates conditions for the precipitation of uniform film-like RA. This stabilized film-like RA provides significant work-hardening capacity which enables the simultaneous achievement of high elongation (26.7%) and a low yield-to-tensile ratio (0.88) while maintaining a high yield strength of 922 MPa. This study introduces a novel strategy for developing high-performance HSLA steels, offering an effective paradigm to address the long-standing challenge of concurrently achieving high elongation and a low yield-to-tensile ratio, which are typically conflicting properties in these materials.

高强度低合金（HSLA）钢因其强度均衡、塑性好和良好的可焊性而成为工程应用的候选材料。然而，由于HSLA钢的低合金含量，在室温下稳定膜状反奥氏体（RA）是困难的，这成为防止高伸率和低屈服拉伸比同时实现的挑战。在本研究中，通过淬火、2%变形冷轧、层状化和回火等工艺，成功地在低合金钢中制备了具有稳定的膜状RA和均匀分布的富cu纳米沉淀物的马氏体基显微组织。结果表明，2%的变形引起位错，有效地控制了新马氏体（FM）的生成，具有较高的长径比（L/D）和4.67%的初始Ni富集。此外，回火过程中Ni元素的分配为均匀膜状RA的析出创造了条件。这种稳定的膜状RA具有显著的加工硬化能力，可以同时实现高伸长率（26.7%）和低屈服-拉伸比（0.88），同时保持922 MPa的高屈服强度。本研究介绍了一种开发高性能HSLA钢的新策略，提供了一种有效的范例，以解决同时实现高伸长率和低屈服-拉伸比的长期挑战，这是这些材料中通常相互冲突的特性。

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引用次数: 0

Optimisation of TiH2–Nb alloy for bone implant using Box–Behnken design: Enhancing strength, elastic modulus and dehydrogenation behaviour through powder metallurgy Box-Behnken设计优化TiH2-Nb合金骨种植体：通过粉末冶金提高强度、弹性模量和脱氢行为

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.mtla.2025.102640

Anis Fatehah Sa’aidi , Hussain Zuhailawati , Ahmad Farrahnoor

Traditional Ti–6Al–4V implants pose challenges due to their high stiffness and potential toxicity, prompting the development of β-type titanium (Ti) alloys with non-toxic alloying elements like niobium (Nb). Titanium hydride (TiH₂) was selected as a precursor due to its improved sinterability, oxidation resistance, and affordability. The TiH₂–Nb alloy was produced through mechanical alloying and powder metallurgy, with optimisation using the Box-Behnken Design (BBD) method. Elemental TiH₂ (60 wt%) and Nb (40 wt%) powders were milled at various speeds (100 to 300 rpm), compacted at 500 MPa, and sintered under an argon atmosphere at temperatures between 800 °C and 1200 °C for 1 to 3 h. Response surface methodology (RSM) identified sintering temperature as the most influential factor on compressive strength and elastic modulus. Optimal conditions, milling at 200 rpm and sintering at 1200 °C for 3 h, yielded in a compressive strength of 1768 MPa and an elastic modulus of 8.7 GPa, closely matching human cortical bone properties. TiH₂–Nb alloy outperformed Ti–Nb alloy in terms of densification (98.56 % relative density), reduced porosity (1.44 %), and desirability score (0.9). Thermogravimetric (TG) analysis confirmed effective dehydrogenation at higher milling speeds due to enhanced Nb diffusion and defect density. X-ray diffraction (XRD) confirmed formation of a dual-phase α+β Ti structure. Optimised TiH₂–Nb alloys offer a promising alternative to Ti–6Al–4V implants, with reduced stress shielding and improved mechanical compatibility for future orthopaedic implants.

传统的Ti - 6al - 4v植入物由于其高刚度和潜在的毒性而面临挑战，促使了β型钛（Ti）合金的发展，其中包括铌（Nb）等无毒合金元素。选择氢化钛（TiH₂）作为前驱体是因为它具有更好的烧结性、抗氧化性和可负担性。通过机械合金化和粉末冶金制备TiH₂-Nb合金，并使用Box-Behnken设计（BBD）方法进行优化。元素TiH 2 （60 wt%）和Nb （40 wt%）粉末以不同的速度（100至300 rpm）研磨，在500 MPa下压实，并在800°C至1200°C的氩气气氛下烧结1至3小时。响应面法（RSM）确定烧结温度是影响抗压强度和弹性模量的最重要因素。在最佳条件下，铣削速度为200转/分，烧结温度为1200℃，烧结时间为3小时，得到的抗压强度为1768 MPa，弹性模量为8.7 GPa，与人类皮质骨的性能非常接近。TiH₂-Nb合金的致密性（相对密度为98.56%）、降低孔隙率（1.44%）和可取性分数（0.9）均优于Ti-Nb合金。热重（TG）分析证实，在较高的铣削速度下，由于Nb扩散和缺陷密度的增强，有效脱氢。x射线衍射（XRD）证实了双相α+β Ti结构的形成。优化的TiH₂-Nb合金为Ti-6Al-4V植入物提供了一种有希望的替代方案，减少了应力屏蔽，提高了未来骨科植入物的机械兼容性。

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引用次数: 0

Quantitative analysis of the geometric fidelity of human bone twins produced by additive manufacturing in hydroxyapatite and Ti-6Al-4V alloy 羟基磷灰石和Ti-6Al-4V合金增材制造人骨孪生体几何保真度的定量分析

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.mtla.2025.102641

Fanny Leborgne , Donatien Campion , Paul Danty , Patricia Pascaud-Mathieu , Jean-Claude Grandidier

Additive manufacturing (AM) opens new opportunities in producing complex shape architectures such as bone scaffolds. Bone tissue features an interconnected lattice microstructure with high porosity and thin wall thickness which are difficult to reproduce with the current AM processes spatial resolutions. This study aims at assessing the feasibility of replicating a human trabecular bone microstructure through laser powder bed fusion and vat-photopolymerization additive technologies. To this purpose, three bone samples were harvested from the tibias of fresh human cadavers and scanned through X-Ray micro-computed tomography. The microstructure of one of these samples was then mimicked using both a Ti-6Al-4V ELI (TA6V) powder and a hydroxyapatite (HA) slurry, shaped by AM processes. The as-built parts were scanned to compare their geometries with the nominal bone model at macroscopic and microscopic scales. This analysis was carried out through image processing by quantifying the dimensional deviations from the reference model on the one hand and by measuring the microstructure parameters on the other hand. Results have shown that the geometries of the TA6V and HA printed parts closely match the bone reference model with dimensional deviations up to 0.02 ± 0.07 mm and 0.06 ± 0.20 mm at scale 1:1 for TA6V and HA replicas respectively. At microscopic level, the material volume fraction of the printed parts is higher than that of the reference model, indicating that further manufacturing parameters optimizations are required to improve the processes resolutions to achieve bone trabeculae characteristic size.

增材制造（AM）为生产复杂形状的结构（如骨支架）提供了新的机会。骨组织具有相互连接的晶格微结构，具有高孔隙率和薄壁厚度，目前的增材制造工艺空间分辨率难以再现。本研究旨在评估通过激光粉末床融合和光聚合添加剂技术复制人小梁骨微观结构的可行性。为此，从新鲜人类尸体的胫骨上采集了三个骨样本，并通过x射线微计算机断层扫描进行了扫描。然后使用Ti-6Al-4V ELI （TA6V）粉末和羟基磷灰石（HA）浆料模拟其中一个样品的微观结构，通过AM工艺成型。在宏观和微观尺度上，对已建成的部件进行扫描，将其几何形状与标称骨模型进行比较。通过图像处理，一方面量化与参考模型的尺寸偏差，另一方面测量微观结构参数，进行分析。结果表明，TA6V和HA打印零件的几何形状与骨参考模型非常接近，尺寸偏差分别为0.02±0.07 mm和0.06±0.20 mm，比例为1:1。在微观水平上，打印部件的材料体积分数高于参考模型，这表明需要进一步优化制造参数以提高工艺分辨率，以实现骨小梁特征尺寸。

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引用次数: 0

Correlative investigation of microstructure, localized corrosion behavior and mechanical properties in hot rolled Mg-Zn-Ca-xEr (x = 0.75, 2, 5, 8 wt%) biodegradable alloys for orthopedic applications 矫形用Mg-Zn-Ca-xEr （x = 0.75, 2, 5, 8 wt%）可生物降解合金的显微组织、局部腐蚀行为和力学性能的相关研究

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.mtla.2025.102643

Divyanshu Aggarwal , Vamsi Krishna Pakki , Sachin Latiyan , Rajesh K. Rajendran , Suraj Singh , Kapil K Gupta , Rajan Ambat , Kaushik Chatterjee , Satyam Suwas , Rajashekhara Shabadi

Magnesium alloys hold immense potential for biodegradable orthopedic implants, yet their rapid degradation, coarse microstructure, and limited ductility hinder clinical translation. This study investigates a novel Mg–1.5Zn–0.5Ca alloy system modified with varying rare earth Erbium (Er) additions (0.75, 2, 5, 8 wt%) and processed through a sequential route of casting, homogenization, and symmetric hot rolling to simultaneously enhance mechanical performance, corrosion resistance, and cytocompatibility. Comprehensive characterization using SEM, EDS, XRD, and EBSD, revealed that 2 wt% Er produced the most refined microstructure, weakened basal texture and uniform W-phase dispersion. In addition, rolling significantly improved grain morphology and suppressed galvanic intermetallic networks, correlating with superior tensile properties (UTS ≈ 236 MPa, elongation ≈ 29 %) and minimized corrosion activity, as confirmed by electrochemical and immersion analyses. Moreover, SECM technique was introduced that demonstrated the lowest localized electrochemical current in 2 wt% Er alloy in rolled state, indicating stable degradation behavior. In addition cytocompatibility assessment using MC3T3-E1 cells validated cell viability above 70 %, meeting ISO 10,993–5 and USFDA standards. This integrated processing–composition approach establishes the rolled Er alloy as a promising candidate for next-generation biodegradable Mg implants, offering an optimal balance of mechanical integrity, corrosion control, and biological safety.

镁合金在生物可降解骨科植入物方面具有巨大的潜力，但其快速降解、粗糙的微观结构和有限的延展性阻碍了临床应用。本研究研究了一种新型Mg-1.5Zn-0.5Ca合金体系，该体系添加了不同的稀土铒（Er）（0.75、2、5、8 wt%），并通过铸造、均匀化和对称热轧的顺序路线进行处理，同时提高了机械性能、耐腐蚀性和细胞相容性。SEM、EDS、XRD、EBSD等综合表征表明，掺量为2 wt% Er的材料微观结构最为细化，基底织构减弱，w相弥散均匀。此外，电化学和浸渍分析证实，轧制显著改善了晶粒形貌，抑制了金属间电网络，具有优异的拉伸性能（UTS≈236 MPa，伸长率≈29%）和最小的腐蚀活性。此外，还介绍了SECM技术，表明2 wt% Er合金在轧制状态下具有最低的局部电化学电流，表明了稳定的降解行为。此外，使用MC3T3-E1细胞进行细胞相容性评估，证实细胞存活率超过70%，符合ISO 10,993-5和USFDA标准。这种综合加工-成分方法使轧制铒合金成为下一代生物可降解镁植入物的有前途的候选材料，提供了机械完整性、腐蚀控制和生物安全性的最佳平衡。

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引用次数: 0

Effect of sintering temperature on the dielectric and impedance properties of high-entropy perovskite oxides (Bi0.2La0.2Ba0.2Sr0.2Ca0.2)TiO3 烧结温度对高熵钙钛矿氧化物（Bi0.2La0.2Ba0.2Sr0.2Ca0.2）TiO3介电和阻抗性能的影响

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-17 DOI: 10.1016/j.mtla.2025.102644

Xiaoyu Wu, Wei Li, Ziheng Huang, Weitian Wang

High-entropy perovskite oxides (HEPOs) constitute a novel class of functional materials in which configurational entropy contributes to the stabilization of unique structural and functional properties. This study investigates the effect of sintering temperature (1100∼1250 °C) on the structural evolution, dielectric behavior, and impedance characteristics of a newly developed A-site quintuple-cation perovskite ceramic, (Bi_0.2La_0.2Ba_0.2Sr_0.2Ca_0.2)TiO₃. X-ray diffraction analysis confirms the formation of a phase-pure tetragonal structure at temperatures exceeding 1200 °C. Microstructural analysis demonstrates temperature-dependent grain growth kinetics: a rapid increase in grain size below 1200 °C (from 0.53 to 1.39 μm) is followed by entropy-suppressed coarsening, resulting in a maximum grain size of 1.50 μm at 1250 °C. This phenomenon is attributed to lattice strain induced by A-site cationic disorder. X-ray photoelectron spectroscopy verifies the presence of multivalent Ti³⁺/Ti⁴⁺ oxidation states and a significant concentration of oxygen vacancies, which form defect dipoles that influence polarization mechanisms. Dielectric spectroscopy reveals exceptional frequency stability within the 10⁴–10⁶ Hz range, with a maximum relative permittivity (ε′) of 3.05 × 10⁵ and a low dielectric loss (tanδ) of 0.05 observed for the sample sintered at 1250 °C. Impedance spectroscopy confirms thermally activated conduction, with reduced resistance and enhanced carrier mobility at higher sintering temperatures, attributed to decreased grain boundary density and optimized defect chemistry. These findings highlight sintering temperature as a key parameter for entropy-mediated property optimization in HEPOs systems, thereby establishing (Bi_0.2La_0.2Ba_0.2Sr_0.2Ca_0.2)TiO₃ as a favorable combination of dielectric properties worthy of further investigation for potential use in high-stability capacitive applications.

高熵钙钛矿氧化物（HEPOs）是一类新型的功能材料，其构型熵有助于稳定其独特的结构和功能特性。本研究研究了烧结温度（1100 ~ 1250℃）对新开发的a位五阳离子钙钛矿陶瓷（Bi0.2La0.2Ba0.2Sr0.2Ca0.2）TiO3的结构演变、介电行为和阻抗特性的影响。x射线衍射分析证实，在温度超过1200℃时，形成了相纯四方结构。显微组织分析表明，温度依赖于晶粒生长动力学：在1200℃以下，晶粒尺寸迅速增大（从0.53到1.39 μm），随后是熵抑制的粗化，在1250℃时晶粒尺寸最大为1.50 μm。这种现象归因于a位阳离子无序引起的晶格应变。x射线光电子能谱证实存在多价Ti3+/Ti4+氧化态和显著浓度的氧空位，它们形成影响极化机制的缺陷偶极子。介电光谱在104-106 Hz范围内具有良好的频率稳定性，在1250°C烧结的样品中，最大相对介电常数（ε′）为3.05 × 105，介电损耗（tanδ）为0.05。阻抗谱证实了热激活传导，在较高的烧结温度下，由于晶界密度降低和缺陷化学优化，电阻降低，载流子迁移率增强。这些发现强调了烧结温度是HEPOs系统中熵介导的性能优化的关键参数，从而建立了（Bi0.2La0.2Ba0.2Sr0.2Ca0.2）TiO3作为一个良好的介电性能组合，值得进一步研究，以潜在地用于高稳定性电容应用。

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引用次数: 0

Defects in MBE grown type-II superlattice multilayers for infrared detectors 红外探测器用MBE生长ii型超晶格多层膜的缺陷

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-15 DOI: 10.1016/j.mtla.2025.102639

R. Goswami , S.B. Qadri

The density and distribution of defects play a crucial role in controlling the performance of the infrared detector. Here we employ high resolution x-ray diffraction topography and high-resolution transmission electron microscopy to investigate the defects structure of the molecular beam epitaxy grown multilayer films, consisting of a two-layer period of InGaSb/InAs, and then a four-layer period of AlGaInSb/InAs/GaInSb/InAs on GaSb (001) substrate. The high-resolution transmission electron microscopy shows the epitaxial growth, with layer defects and dislocations in both types of superlattices. The multilayer spacings were measured using the superlattice peaks of the x-ray diffraction patterns, as the spacing between these satellite peaks is directly related to the superlattice period. The spacing turns out to be 7.2 nm and 10.4 nm for two and four periods, respectively, consistent with the transmission electron microscopy measurements. The strain between multilayers has been estimated by analyzing the symmetric and asymmetric reflections. The estimated strain is 0.04%, suggesting the superior growth of the superlattice layers. The dislocation density in the two-period and four-period layers, estimated from the HRTEM images, is ≈ 1.7×10¹⁶ m⁻², which is considerably high and consistent with the estimated dislocation density obtained from the XRD peak broadening. Such high density of defects, originated during the multilayer growth due to differential thermal mismatch between layers, can affect the film quality and increase the dark noise of the detector.

缺陷的密度和分布对红外探测器的性能起着至关重要的控制作用。本文采用高分辨率x射线衍射形貌和高分辨率透射电镜研究了在GaSb（001）衬底上生长的由两层InGaSb/InAs和四层AlGaInSb/InAs/GaInSb/InAs组成的分子束外延多层薄膜的缺陷结构。高分辨率透射电镜显示外延生长，在两种类型的超晶格中都有层缺陷和位错。利用x射线衍射图的超晶格峰测量多层间距，因为这些卫星峰之间的间距与超晶格周期直接相关。两个和四个周期的间距分别为7.2 nm和10.4 nm，与透射电镜测量结果一致。通过对对称反射和非对称反射的分析，估计了多层间的应变。估计应变为0.04%，表明超晶格层生长良好。HRTEM图像估计的二周期和四周期层的位错密度为≈1.7×1016 m−2，这与XRD峰展宽估计的位错密度一致。这种高密度的缺陷是在多层生长过程中由于层与层之间的热差失配而产生的，会影响薄膜质量并增加探测器的暗噪声。

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引用次数: 0

Enhanced creep resistance of additively manufactured UNS N07001 by electron beam melting 电子束熔炼增强增材制造UNS N07001抗蠕变性能

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-14 DOI: 10.1016/j.mtla.2025.102638

Ryo Takakuwa , Motoki Sakaguchi , Hiroaki Nakamoto , Ryotaro Yamamoto , Manabu Noguchi , Hirotsugu Inoue

The nickel-based superalloy UNS N07001 (also known as Waspaloy®), commonly used in gas turbine components, is conventionally manufactured through forging, but electron beam powder bed fusion (EB-PBF) is an emerging additive manufacturing method offering faster production. The effects of post-heat treatments on the microstructure and creep behavior of UNS N07001 built by EB-PBF were investigated in this study. Specimens were evaluated in three conditions: as-built, after hot isostatic pressing (HIP) alone, and combined with solution treatment and aging (STA) after HIP. In the microstructural analysis, all specimens consistently exhibited a columnar grain structure aligned with the building direction, and HIP treatment effectively eliminated the internal defects observed in the as-built specimen. STA after HIP treatment promoted the precipitation of fine secondary γ' phase and discretely formed M₂₃C₆ carbides at the grain boundaries, thereby reducing the area fraction of the coarser primary γ' phase. Stress-rupture tests were performed at 732 and 816 °C with the load axis aligned parallel to the building direction, showing that the HIP + STA specimens outperformed both the AMS5704L and the wrought material. This superior creep resistance is attributed to the synergistic effect of the macro-scale columnar grain structure, which minimizes grain boundaries perpendicular to the load, and the optimized intragranular microstructure, which provides high resistance against dislocation movement. Ultimately, EB-PBF with optimized post-heat treatment is a highly promising manufacturing route for UNS N07001 components.

镍基高温合金UNS N07001（也称为Waspaloy®）通常用于燃气轮机部件，传统上是通过锻造制造的，但电子束粉末床熔合（EB-PBF）是一种新兴的增材制造方法，可提供更快的生产速度。研究了热处理对EB-PBF制备的UNS N07001显微组织和蠕变行为的影响。在三种条件下对样品进行评估：建成时，单独热等静压（HIP）后，以及热等静压后结合固溶处理和时效（STA）。在显微组织分析中，所有试样均表现出与构建方向一致的柱状晶粒结构，HIP处理有效地消除了构建试样中观察到的内部缺陷。热处理后的STA促进了细小的次生γ′相的析出，并在晶界处离散地形成了M23C6碳化物，从而降低了较粗的初生γ′相的面积分数。在732°C和816°C下，在荷载轴与建筑方向平行的情况下进行应力断裂试验，结果表明，HIP + STA试样的性能优于AMS5704L和变形材料。这种优异的抗蠕变性能是由于宏观柱状晶粒结构的协同作用，使垂直于载荷的晶界最小化，而优化的晶内组织则提供了高的位错运动阻力。最终，经过优化后热处理的EB-PBF是一种非常有前途的UNS N07001组件制造路线。

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引用次数: 0

Magnetic behaviour of FeCo-2V under applied stress and elevated temperature FeCo-2V在外加应力和高温下的磁性行为

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-13 DOI: 10.1016/j.mtla.2025.102636

Sirapob Toyting , Christopher W. Harrison , Alexis Lambourne , Howard J. Stone

FeCo-2V alloys are promising candidates for high-performance electric machines, such as those used in aerospace and electrification, owing to their exceptional saturation magnetisation and potential to maximise power density. Nevertheless, their magnetic behaviour under mechanical loading and at elevated temperatures remains insufficiently understood. In this study, the stress- and temperature-dependent magnetic and electrical properties of FeCo-2V were investigated separately, with particular attention to coercivity, core losses, and underlying mechanisms. Stress-dependent experiments revealed three distinct regimes. Under compressive loading, magnetic performance deteriorated, as shown by expanding hysteresis loops and increased coercivity and core losses due to hard-axis magnetisation. In the tensile regime below ∼100 MPa, performance improved through stress-assisted easy-axis alignment. At higher tensile stresses, however, micro-yielding dominated: increasing Kernel Average Misorientation (KAM) angles indicated enhanced dislocation densities, which in turn degraded magnetic properties. Independent temperature-dependent studies demonstrated that coercivity decreases systematically with increasing temperature, attributed to reduced anisotropy energy that facilitates domain wall motion. Core losses also declined with temperature, with loss-separation analysis confirming reductions in both hysteresis and eddy current loss coefficients. Additionally, electrical resistivity was observed to increase with temperature, consistent with the Drude model and a reduced eddy current loss coefficient.

feo - 2v合金具有优异的饱和磁化性能和最大化功率密度的潜力，是高性能电机（如航空航天和电气化领域）的有希望的候选者。然而，它们在机械载荷和高温下的磁性行为仍然没有得到充分的了解。在本研究中，分别研究了feo - 2v的应力和温度相关的磁性和电学性能，特别关注矫顽力、铁芯损耗和潜在的机制。应力相关实验揭示了三种不同的机制。在压缩载荷下，磁性性能恶化，表现为磁滞回线扩大，硬轴磁化导致矫顽力和磁芯损耗增加。在低于~ 100 MPa的拉伸状态下，通过应力辅助易轴对准提高了性能。然而，在较高的拉伸应力下，微屈服占主导地位：增加核平均错取向（KAM）角表明位错密度增加，从而降低了磁性能。独立的温度相关研究表明，矫顽力随着温度的升高而系统地降低，这是由于各向异性能量的降低促进了畴壁的运动。磁芯损耗也随着温度的升高而下降，损耗分离分析证实了磁滞和涡流损耗系数的降低。此外，电阻率随温度升高而升高，与Drude模型一致，涡流损耗系数降低。

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引用次数: 0

Characterisation of MX precipitate density and irradiation hardening in advanced reduced-activation ferritic-martensitic fusion steels 高级低活化铁素体-马氏体熔合钢中MX沉淀密度和辐照硬化的表征

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-13 DOI: 10.1016/j.mtla.2025.102635

James S.K.L. Gibson , Alex Carruthers , Benjamin R.S. Evans , Jack Haley , Slava Kuksenko , Kay Song , Luke Hewitt , Stephen Jones , Shahin Mehraban , Nicholas Lavery , David Bowden

Reduced activation ferritic-martensitic (RAFM) steels are a recent class of radiation-resistant steels designed for the structural components of power-producing fusion reactors. In this work an advanced (A)RAFM steel has been developed with superior radiation hardening resistance with respect to the EUROFER-97 upon which it was based.

4D-STEM (scanning transmission electron microscopy) has been combined with a novel processing methodology to visualise all the fine MX precipitates that led to this outstanding radiation hardening resistance and determine a precipitate density of 5 × 10²² m^-3.

Self-ion irradiation campaigns up to 100 dpa at 350 °C show an increase in hardness of only 35 % at 10 dpa where EUROFER-97 exhibits a near-doubling of its hardness. The initial work hardening response, as determined from spherical nanoindentation, is unchanged between the as-received state and irradiation to 100 dpa, implying that the alloy should retain reasonable ductility under these conditions. Proton irradiations at 250 °C, 350 °C, and 400 °C demonstrate that the low temperature hardening embrittlement threshold of the new steel is largely unaffected, increasing by only ∼50 °C with respect to EUROFER-97.

A refinement of alloy chemistry and a subsequent modification of the thermomechanical treatments to favour MX precipitates is therefore a very promising strategy for the further development of fusion steels.

低活化铁素体-马氏体（RAFM）钢是一种新型的抗辐射钢，主要用于核聚变反应堆的结构部件。在这项工作中，开发了一种先进的(A)RAFM钢，相对于其基础的EUROFER-97具有优异的抗辐射硬化性。4D-STEM（扫描透射电子显微镜）与一种新颖的处理方法相结合，可以可视化所有细小的MX沉淀，这些沉淀导致了出色的抗辐射硬化性，并确定了5 × 1022 m-3的沉淀密度。在350℃下高达100 dpa的自离子辐照运动显示，在10 dpa时硬度仅增加35%，而EUROFER-97的硬度几乎增加了一倍。由球形纳米压痕测定的初始加工硬化响应在接收状态和辐照至100 dpa之间没有变化，这意味着合金在这些条件下应保持合理的延展性。250°C、350°C和400°C的质子辐照表明，新钢的低温硬化脆化阈值基本上不受影响，与EUROFER-97相比仅提高了~ 50°C。因此，合金化学的改进和随后的热处理方法的改进有利于MX沉淀，是进一步发展熔合钢的一个非常有前途的策略。

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引用次数: 0

Cellulose nanofibers in ice: microstructural effects on mechanical response 冰中的纤维素纳米纤维：微观结构对力学响应的影响

IF 2.9 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materialia

Pub Date : 2025-12-12 DOI: 10.1016/j.mtla.2025.102633

Emily Asenath-Smith , Kiera L. Thompson Towell , Matthew A. Fort, Nicholas P. Wilder

Abundant in cold regions, ice rarely exists as a pure single-phase compound but rather contains insoluble particulates and fibrous matter from the local environment. Such second phase materials can drastically change the formation mechanism, microstructure, and properties of the resulting composite ice. Cellulose nanofibers (CNFs) were investigated for their ability to strengthen ice and studied with optical microscopy, ice fabric analysis, and mechanical property measurements. With increasing concentration, the CNFs bridged across grain boundaries and were distributed throughout grain interiors, forming a percolated network within the ice microstructure. The CNFs in ice were found to modify the ice fabric from an S2 classification to one with an irregular distribution of c-axis for intermediate CNF wt%, and appeared to shift back towards S2 as CNF was increased to 1.0 wt%. The addition of up to 1.0 wt% CNF to ice increased the flexural strength from 3.1 MPa to 5.8 MPa in 3-point bending and from 1.7 MPa to 3.8 MPa in 4-point bending, while increasing the compressive strength from 2.6 MPa to 7.2 MPa. The increase in strength correlated with ductility imparted by the CNFs which thereby increased the apparent toughness by a factor of 2 – 10 compared to pure ice. These insights reveal the mechanistic response of CNFs in ice and open future avenues that utilize ice as a high-performance material for structures in cold regions.

在寒冷地区，冰很少以纯单相化合物的形式存在，而是含有来自当地环境的不溶性颗粒和纤维物质。这种第二相材料可以极大地改变合成冰的形成机制、微观结构和性能。研究了纤维素纳米纤维（CNFs）增强冰的能力，并通过光学显微镜、冰织物分析和力学性能测量进行了研究。随着浓度的增加，CNFs跨越晶界，分布在晶粒内部，在冰微观结构内形成一个渗透网络。研究发现，在中间CNF wt%时，冰中的CNF将冰结构从S2分类改变为不规则的c轴分布，当CNF增加到1.0 wt%时，冰结构似乎又向S2方向移动。在冰中加入1.0 wt%的CNF， 3点弯曲强度从3.1 MPa增加到5.8 MPa， 4点弯曲强度从1.7 MPa增加到3.8 MPa，抗压强度从2.6 MPa增加到7.2 MPa。强度的增加与CNFs所赋予的延性有关，因此与纯冰相比，CNFs的表观韧性增加了2 - 10倍。这些见解揭示了CNFs在冰中的机制响应，并开辟了利用冰作为寒冷地区结构的高性能材料的未来途径。

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引用次数: 0