Intermetallics最新文献_第10页

Effect of initial grain size on the interfacial bonding behavior of CoCrFeMnNi high-entropy alloy joints produced by vacuum hot-compression bonding 初始晶粒尺寸对真空热压结合CoCrFeMnNi高熵合金接头界面结合行为的影响

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-11-03 DOI: 10.1016/j.intermet.2025.109048

Chuanzong Li , Chuansen Fan , Junmei Chen , Jijin Xu , Jieshi Chen , Hao Lu , Chun Yu

Vacuum hot-compression bonding (VHCB) technology exhibits irreplaceable advantages in manufacturing critical components of high-entropy alloys (HEAs). Although the bonding mechanism of the VHCB process has been widely investigated, its dependence on the initial grain size remains to be further clarified. The interfacial bonding behavior of CoCrFeMnNi HEA VHCB joints with different initial grain sizes was systematically investigated. The results indicate that the reduction in initial grain size, on the one hand, improves diffusion conditions of interfacial atomic, accelerating the dissolution of interfacial oxide particles, and on the other hand, enhances the kinetics of interfacial dynamic recrystallization and promotes the migration of interfacial grain boundaries (IGBs). The IGB migration process for fine-grained joints results from the combined effects of discontinuous dynamic recrystallization, twin-induced interfacial boundary migration, and triple junction transformation. In contrast, the elimination of IGBs in coarse-grained joints is mainly related to the evolution of discontinuous and continuous dynamic recrystallized grains. The mechanical analysis results demonstrate that the enhanced strengthening effects in the fine-grained joint not only improve the strength of the joint but also optimize its failure mode during fracture. The initial grain size changed from 149.6 μm to 7.8 μm, and the recovery rates of ultimate tensile strength and elongation of the joint increased from 88.6 % and 54.3 % to 102.2 % and 104.6 %, respectively, reflecting the gradual enhancement of the interfacial bonding quality.

真空热压键合（VHCB）技术在制造高熵合金（HEAs）关键部件方面具有不可替代的优势。虽然VHCB工艺的键合机制已经得到了广泛的研究，但其与初始晶粒尺寸的依赖关系仍有待进一步阐明。系统研究了不同初始晶粒尺寸的CoCrFeMnNi HEA - VHCB接头的界面结合行为。结果表明：初始晶粒尺寸的减小，一方面改善了界面原子的扩散条件，加速了界面氧化物颗粒的溶解；另一方面，增强了界面动态再结晶动力学，促进了界面晶界的迁移。细晶节理的IGB迁移过程是由不连续动态再结晶、双致界面边界迁移和三重结转变共同作用的结果。而粗晶节理中IGBs的消除主要与不连续和连续动态再结晶晶粒的演化有关。力学分析结果表明，细晶节理中强化效应的增强不仅提高了节理的强度，而且优化了节理断裂时的破坏模式。初始晶粒尺寸从149.6 μm增加到7.8 μm，接头的极限抗拉强度和伸长率分别从88.6%和54.3%增加到102.2%和104.6%，界面结合质量逐渐提高。

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引用次数: 0

Comparison of microstructure and mechanical properties of Fe3Al/TiC coatings produced by cold gas spray and high velocity oxygen fuel 低温气体喷射和高速氧燃料制备Fe3Al/TiC涂层的显微组织和力学性能比较

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-11-02 DOI: 10.1016/j.intermet.2025.109052

Genís Clavé , Lorena Betancor-Cazorla , Camila Barreneche , Anna Martín Vilardell , Sergi Dosta

Fe₃Al powders reinforced with TiC were synthesized and deposited as coatings using Cold Gas Spraying (CGS) and High-Velocity Oxy-Fuel (HVOF) techniques. Fe₃Al intermetallic compounds are known for their excellent resistance to sulfidizing and carburizing environments. However, their mechanical properties can be enhanced through reinforcement with TiC particles. The Fe₃Al/TiC feedstock powder was produced via agglomeration and sintering, resulting in a homogeneous distribution of TiC particles around the Fe₃Al matrix. Coatings were deposited onto AISI 316L stainless steel substrates and characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), as well as adhesion and erosion tests. The results indicate that CGS coatings exhibit lower oxidation levels, whereas HVOF coatings demonstrate superior adhesion and hardness due to their denser microstructure and greater particle deformation. Hardness increased with the incorporation of TiC. Erosion testing revealed that CGS coatings performed better, attributed to their reduced brittleness compared to HVOF coatings. These findings highlight the potential of Fe₃Al/TiC coatings for high-temperature and wear-resistant applications. Moreover, the study demonstrates that comparable performance can be achieved using CGS as with HVOF for depositing Fe₃Al/TiC intermetallic coatings.

采用冷气喷涂（CGS）和高速氧燃料（HVOF）技术合成了TiC增强Fe3Al粉末并沉积成涂层。Fe3Al金属间化合物以其优异的耐硫化和渗碳环境而闻名。然而，它们的力学性能可以通过TiC颗粒增强来提高。通过团聚和烧结制备Fe3Al/TiC原料粉末，使TiC颗粒均匀分布在Fe3Al基体周围。采用x射线衍射（XRD）、扫描电镜（SEM）、能量色散x射线能谱（EDX）以及附着力和侵蚀试验对涂层进行了表征。结果表明，CGS涂层具有较低的氧化水平，而HVOF涂层由于其更致密的微观结构和更大的颗粒变形而具有更好的附着力和硬度。随着TiC的掺入，硬度增加。腐蚀测试表明，CGS涂层性能更好，因为与HVOF涂层相比，CGS涂层的脆性降低了。这些发现突出了Fe3Al/TiC涂层在高温和耐磨应用中的潜力。此外，研究表明，使用CGS可以获得与HVOF相当的性能，用于沉积Fe3Al/TiC金属间涂层。

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引用次数: 0

Microstructural evolution and property enhancement of CoCrFeNiTax high-entropy alloys by laser remelting 激光重熔CoCrFeNiTax高熵合金的组织演变及性能增强

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-11-02 DOI: 10.1016/j.intermet.2025.109056

Peng Lyu , Mingxuan Jiang , Jia Xia , Shun Guo , Yu Liu , Xinlin Liu , Haixia Liu

The present study employed laser remelting (LR) technology to control the microstructure of CoCrFeNiTa_x high-entropy alloys (HEAs). The microstructural evolution and performance changes of the alloys before and after LR were systematically analyzed. The results showed that the original CoCrFeNiTa_x alloys exhibited a dual phase structure of FCC and Laves, with the fraction of the Laves phase increasing with Ta content. At higher Ta levels, a typical FCC + Laves hypereutectic structure was formed. During wear testing, the increase in Ta content promoted an oxidative wear mechanism, thereby improving the wear resistance of the alloys. Electrochemical corrosion tests further demonstrated that Ta addition enhanced passive film formation, which effectively restrained Cl⁻-induced corrosion. Ultimately, this effect significantly improved the corrosion resistance of the alloys. After LR, the grains were markedly refined, and a dense remelted layer (600–1000 μm) was formed on the surface. At the same time, the hardness and wear resistance were greatly enhanced, mainly due to the combined effects of solid-solution strengthening, second-phase strengthening, and grain-refinement strengthening. In addition, the inhibitory effect of the passive film on corrosion was substantially reinforced. Among all compositions, the LR-Ta_0.5 alloy exhibited the hightest resistance to wear and corrosion. These findings demonstrated that LR technology could effectively modify the surface of HEAs and provide valuable experimental support for the surface modification of CoCrFeNiTa_x HEAs.

采用激光重熔（LR）技术控制CoCrFeNiTax高熵合金（HEAs）的显微组织。系统分析了合金在LR前后的组织演变和性能变化。结果表明：CoCrFeNiTax合金呈现FCC相和Laves相的双相结构，Laves相的比例随着Ta含量的增加而增加；在较高Ta水平下，形成典型的FCC + Laves过共晶结构。在磨损试验中，Ta含量的增加促进了合金的氧化磨损机制，从而提高了合金的耐磨性。电化学腐蚀试验进一步表明，Ta的加入促进了钝化膜的形成，有效地抑制了Cl−引起的腐蚀。最终，这种效应显著提高了合金的耐腐蚀性。再熔后，晶粒明显细化，表面形成致密的重熔层（600 ~ 1000 μm）。同时，硬度和耐磨性得到了很大的提高，这主要是固溶强化、第二相强化和晶粒细化强化的共同作用。此外，钝化膜对腐蚀的抑制作用得到了显著增强。其中，LR-Ta0.5合金的耐磨性和耐蚀性最高。结果表明，LR技术可以有效修饰HEAs的表面，为CoCrFeNiTax HEAs的表面修饰提供了有价值的实验支持。

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引用次数: 0

Study on microstructure and property of novel γ′-strengthened multi-component Co-based superalloys 新型γ′强化多组分co基高温合金的组织与性能研究

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-10-31 DOI: 10.1016/j.intermet.2025.109054

Feikuo Chen , Zeting Du , Dawei Wei , Jiejie Shi , Cuiping Guo

Four novel Co-based superalloys were designed based on the thermodynamic database. A preliminary evaluation was conducted on the compression mechanical properties, density, and transition temperature of alloys. After aging at 1000 °C for 720 h, the alloys exhibited a stable γ/γʹ two-phase microstructure, and no harmful secondary phase, such as the topologically close-packed phase (TCP), was observed in the alloys. The novel Co-based superalloy Co30.0Ni9.0Al3.0W1.0Ta4.0Ti9.0Cr (at.%) possesses a higher γʹ solvus temperature (1117 ± 2 °C) and a lower density (8.55 ± 0.03 g/cm³). Furthermore, the yield strength exhibits a positive temperature dependence from room temperature to 600 °C in the compression process. The yield strength of the alloy is 797 ± 3 MPa at 600 °C, which is appreciably higher than that of the commercial Mar-M-509 superalloy.

基于热力学数据库，设计了四种新型钴基高温合金。对合金的压缩力学性能、密度和转变温度进行了初步评价。在1000℃时效720 h后，合金表现出稳定的γ/γ′两相组织，合金中未观察到有害的二次相，如拓扑紧密堆积相（TCP）。新型co基高温合金Co30.0Ni9.0Al3.0W1.0Ta4.0Ti9.0Cr （at.%）具有较高的γ′溶剂温度（1117±2℃）和较低的密度（8.55±0.03 g/cm3）。此外，在压缩过程中，屈服强度表现出从室温到600℃的正温度依赖关系。该合金在600℃时的屈服强度为797±3 MPa，明显高于商用Mar-M-509高温合金。

引用次数: 0

Strengthening mechanisms and corrosion resistance of Al15Cr15Fe50Ni20-xBx (x = 2, 4, and 6) low-density high-entropy alloys Al15Cr15Fe50Ni20-xBx （x = 2、4和6）低密度高熵合金的强化机理和耐蚀性

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-10-31 DOI: 10.1016/j.intermet.2025.109051

Bo Li , Yu Yang , Wanqing Chen , Han Yang , Xicong Ye , Dong Fang

Interstitial atom doping has been demonstrated to effectively enhance the mechanical properties of high-entropy alloys (HEAs); however, its influence on corrosion resistance and the associated mechanisms remains insufficiently elucidated. In the present work, a series of B-doped low-density HEAs, Al₁₅Cr₁₅Fe₅₀Ni_20-xB_x (x = 2, 4, and 6), were synthesized via vacuum arc melting. The phase constituents and microstructural features were systematically characterized, and the structure–property relationships related to mechanical strengthening and corrosion behavior were investigated. The alloys comprise FCC, BCC, and boride phases. Specifically, Al₁₅Cr₁₅Fe₅₀Ni₁₈B₂ and Al₁₅Cr₁₅Fe₅₀Ni₁₆B₄ exhibit hypoeutectic microstructures, while Al₁₅Cr₁₅Fe₅₀Ni₁₄B₆ exhibits a hypereutectic structure. With increasing B content, the alloy density decreases from 6.80 g/cm³ to 6.42 g/cm³, classifying these alloys as low-density HEAs (ρ < 7.00 g/cm³). Strengthening analysis suggests that precipitation hardening (563.96 MPa) and grain refinement (372.18 MPa) are the dominant mechanisms, whereas solid solution strengthening (69.87 MPa) provides a supplementary contribution. Corrosion resistance evaluation reveals that the thickness of the surface passive film decreases progressively with B addition, which is closely associated with reduced Cr content in the matrix and increased elemental metal deposition. Localized galvanic coupling accelerates the preferential dissolution of the Ni- and Al-enriched BCC phase. Among the alloys investigated, Al₁₅Cr₁₅Fe₅₀Ni₁₈B₂ demonstrates the most favorable corrosion resistance, exhibiting a corrosion potential (E_corr = −187.86 mV) and corrosion current density (I_corr = 0.0164 μA/cm²), superior to those of 316L stainless steel and most conventional alloys.

研究表明，间隙原子掺杂能有效提高高熵合金的力学性能；然而，其对耐蚀性的影响及其相关机制尚未得到充分阐明。本文采用真空电弧熔炼法制备了一系列掺杂b的低密度HEAs Al15Cr15Fe50Ni20-xBx （x = 2、4和6）。系统表征了相组成和微观组织特征，研究了与力学强化和腐蚀行为相关的组织-性能关系。合金包括FCC相、BCC相和硼化物相。Al15Cr15Fe50Ni18B2和Al15Cr15Fe50Ni16B4表现为亚共晶组织，而Al15Cr15Fe50Ni14B6表现为过共晶组织。随着B含量的增加，合金密度从6.80 g/cm3降至6.42 g/cm3，属于低密度HEAs （ρ < 7.00 g/cm3）。强化分析表明，沉淀硬化（563.96 MPa）和晶粒细化（372.18 MPa）是主要的强化机制，固溶强化（69.87 MPa）起辅助作用。耐蚀性评价表明，随着B的加入，表面钝化膜的厚度逐渐减小，这与基体中Cr含量的降低和金属元素沉积的增加密切相关。局部电偶联加速了富集Ni和al的BCC相的优先溶解。其中，Al15Cr15Fe50Ni18B2的腐蚀电位（Ecorr =−187.86 mV）和腐蚀电流密度（Icorr = 0.0164 μA/cm2）均优于316L不锈钢和大多数常规合金。

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引用次数: 0

Coupling relationship between microstructure and high-temperature oxidation mechanism in alloying element-guided eutectic high-entropy alloys 元素导向共晶高熵合金显微组织与高温氧化机理的耦合关系

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-10-30 DOI: 10.1016/j.intermet.2025.109055

Shan Wang , Yan Cui , Yangchuan Cai , Xiaohua Wang , Jinyao Mu , Yan Zhao

This study investigates the high-temperature oxidation behavior of three high-entropy alloys (HEAs) with distinct eutectic microstructures: hypoeutectic FeCoNi_2.0Cr_1.2Mo_0.2Nb_0.5 (Nb_0.5), eutectic FeCoNi_2.0Cr_1.2Mo_0.2Nb_0.63 (Nb_0.63), and hypereutectic FeCoNi_2.0Cr_1.2Mo_0.2Nb_0.9 (Nb_0.9). All three HEAs exhibit a dual-phase microstructure comprising FCC and HCP phases. The oxidation behavior was evaluated after 100 h of isothermal exposure at 600 °C and 800 °C. The results demonstrate that the oxidation kinetics of all alloys follow a parabolic rate law, indicating diffusion-controlled mechanisms. Characterization via XRD, XPS, and SEM revealed that the oxide scale is predominantly Cr₂O₃, which preferentially nucleates at grain boundaries and subsequently covers the entire surface. Among these, the Nb_0.63 EHEA exhibited the highest oxidation resistance, rapidly forming a continuous and dense Cr₂O₃ scale in the initial oxidation stage, which effectively impeded the outward diffusion of metal ions and the inward diffusion of oxygen. During oxidation at 800 °C, acicular Nb-rich precipitates formed within the FCC phase of all three alloys. These precipitates act as more effective barriers against oxygen ion diffusion than the parent phase, further enhancing the oxidation resistance. This work elucidates the synergistic mechanism between the eutectic microstructure and precipitation behavior on the oxidation resistance of HEAs, providing a theoretical and experimental basis for designing novel high-entropy alloys with superior high-temperature oxidation resistance.

本文研究了三种不同共晶组织的高熵合金（HEAs）的高温氧化行为：亚共晶FeCoNi2.0Cr1.2Mo0.2Nb0.5 （Nb0.5）、共晶FeCoNi2.0Cr1.2Mo0.2Nb0.63 （Nb0.63）和过共晶FeCoNi2.0Cr1.2Mo0.2Nb0.9 （Nb0.9）。三种HEAs均表现为FCC相和HCP相的双相结构。在600°C和800°C等温暴露100 h后评估氧化行为。结果表明，所有合金的氧化动力学都遵循抛物线速率规律，表明了扩散控制机制。XRD、XPS和SEM表征表明，氧化垢主要为Cr2O3，在晶界处优先成核，随后覆盖整个表面。其中，Nb0.63 EHEA的抗氧化性最高，在氧化初期迅速形成连续致密的Cr2O3垢，有效地阻碍了金属离子向外扩散和氧向内扩散。在800℃氧化过程中，三种合金的FCC相均形成针状富铌析出物。这些沉淀比母相更有效地阻止氧离子扩散，进一步增强了抗氧化性。本研究阐明了共晶组织和析出行为对HEAs抗氧化性能的协同作用机制，为设计新型高熵高温抗氧化合金提供了理论和实验依据。

{"title":"Coupling relationship between microstructure and high-temperature oxidation mechanism in alloying element-guided eutectic high-entropy alloys","authors":"Shan Wang , Yan Cui , Yangchuan Cai , Xiaohua Wang , Jinyao Mu , Yan Zhao","doi":"10.1016/j.intermet.2025.109055","DOIUrl":"10.1016/j.intermet.2025.109055","url":null,"abstract":"<div><div>This study investigates the high-temperature oxidation behavior of three high-entropy alloys (HEAs) with distinct eutectic microstructures: hypoeutectic FeCoNi2.0Cr1.2Mo0.2Nb0.5 (Nb0.5), eutectic FeCoNi2.0Cr1.2Mo0.2Nb0.63 (Nb0.63), and hypereutectic FeCoNi2.0Cr1.2Mo0.2Nb0.9 (Nb0.9). All three HEAs exhibit a dual-phase microstructure comprising FCC and HCP phases. The oxidation behavior was evaluated after 100 h of isothermal exposure at 600 °C and 800 °C. The results demonstrate that the oxidation kinetics of all alloys follow a parabolic rate law, indicating diffusion-controlled mechanisms. Characterization via XRD, XPS, and SEM revealed that the oxide scale is predominantly Cr2O3, which preferentially nucleates at grain boundaries and subsequently covers the entire surface. Among these, the Nb0.63 EHEA exhibited the highest oxidation resistance, rapidly forming a continuous and dense Cr2O3 scale in the initial oxidation stage, which effectively impeded the outward diffusion of metal ions and the inward diffusion of oxygen. During oxidation at 800 °C, acicular Nb-rich precipitates formed within the FCC phase of all three alloys. These precipitates act as more effective barriers against oxygen ion diffusion than the parent phase, further enhancing the oxidation resistance. This work elucidates the synergistic mechanism between the eutectic microstructure and precipitation behavior on the oxidation resistance of HEAs, providing a theoretical and experimental basis for designing novel high-entropy alloys with superior high-temperature oxidation resistance.</div></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":"188 ","pages":"Article 109055"},"PeriodicalIF":4.8,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145424916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Transient liquid phase sintering with nanophase reinforcement enables silver joints with low thermal resistance and high shear strength 纳米相增强的瞬态液相烧结使银接头具有低热阻和高抗剪强度

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-10-29 DOI: 10.1016/j.intermet.2025.109059

Yiming Xu , Jiaying Zhang , Xuanjue Hu , Yiding Yu , Wenhao Gao , Jinhua Qin , Yunzhu Ma , Wensheng Liu , Siwei Tang , Zhongkun Lin , He Wang

High-power semiconductor devices demand reliable interconnects that can be processed at low temperatures and pressures without sacrificing performance. To address this need, a composite solder paste consisting of InSn alloy and silver powder was used to join copper substrates at 200 °C under 5 MPa. The incorporation of InSn significantly improved sintering densification, reducing porosity to 1.96 % at an optimal content of 20 wt%. At this condition, uniformly dispersed Ag₃(In,Sn) nanoparticles (∼205 nm) within the joint provided dispersion strengthening, while a dense, continuous Cu₆(In,Sn)₅ intermetallic compound (IMC) layer at the interface contributed to strong metallurgical bonding. This dual reinforcement mechanism elevated the joint's shear strength to 25.8 MPa. Although the alloy addition slightly increased the intrinsic thermal resistance, the sharp drop in porosity at 20 wt% led to a low effective thermal resistance of 2.39 mm² K/W. This study presents a viable pathway for engineering high-performance, low-temperature sintering pastes tailored for advanced power electronics packaging.

高功率半导体设备需要可靠的互连，可以在低温和低压下处理，而不会牺牲性能。为了满足这一需求，使用由InSn合金和银粉组成的复合锡膏在200°C和5 MPa下连接铜衬底。InSn的掺入显著改善了烧结致密性，在最佳含量为20% wt%时，孔隙率降至1.96%。在此条件下，界面内均匀分散的Ag3（In,Sn）纳米颗粒（~ 205 nm）提供了弥散强化，而界面处致密连续的Cu6(In,Sn)5金属间化合物（IMC）层有助于增强冶金结合。双配筋机制使节理抗剪强度达到25.8 MPa。虽然合金的加入略微增加了固有热阻，但孔隙率在20 wt%时急剧下降导致有效热阻较低，为2.39 mm2 K/W。这项研究为高性能低温烧结浆料的工程设计提供了一条可行的途径，该浆料可用于先进的电力电子封装。

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引用次数: 0

L12 nano-precipitates-driven microstructural design for enhanced oxidation resistance of CoCrNi-based medium-entropy alloys 增强cocrni基中熵合金抗氧化性能的L12纳米析出物驱动显微组织设计

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-10-27 DOI: 10.1016/j.intermet.2025.109049

Zhiyi Ding , Junjie Liu , Xiaohong Chen , Aiying Chen , Tong Wang , Bin Gan , Jinchao Song

Driven by advancements in aerospace and gas turbine technologies, CoCrNi-based medium-entropy alloys (MEAs) have emerged as promising high-temperature structural materials due to their exceptional thermomechanical properties. Although the incorporation of γ′-forming elements (Al, Ti) enhances strength via nanoscale precipitate strengthening, it often compromises the alloy's inherent oxidation resistance. To resolve this, the present study systematically optimized the base-element composition of a Co-Cr-Ni-based MEA, with isothermal oxidation behavior investigated at 800 °C for 600 h in air. The results demonstrate that a Ni-rich composition exhibits superior oxidation resistance and structural stability, attributed to its high-density γ/γ′ dual-phase structure which promotes the formation of a stable protective scale mainly composed of Al₂O₃ and Cr₂O₃, minimizes internal oxidation, and effectively suppresses spallation. In contrast, CoCrNi-based and Co-rich alloy suffer from severe spallation due to grain boundary widening. This work establishes a foundational strategy for enhancing the environmental durability and mechanical performance of CoCrNi-based MEAs, facilitating their application in next-generation high-temperature systems.

在航空航天和燃气轮机技术进步的推动下，cocrni基中熵合金（MEAs）因其优异的热机械性能而成为有前途的高温结构材料。虽然γ′形成元素（Al, Ti）的加入通过纳米级析出强化提高了强度，但它往往会损害合金固有的抗氧化性。为了解决这个问题，本研究系统地优化了co - cr - ni基MEA的基本元素组成，并在空气中800°C、600 h的等温氧化行为进行了研究。结果表明，富ni成分具有较高的抗氧化性和结构稳定性，其高密度的γ/γ′双相结构促进了主要由Al2O3和Cr2O3组成的稳定保护层的形成，减少了内部氧化，有效地抑制了剥落。而cocrni基和富co合金由于晶界变宽而出现严重的剥落。这项工作为提高基于cocrni的mea的环境耐久性和机械性能建立了基础策略，促进了它们在下一代高温系统中的应用。

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引用次数: 0

Revealing the role of low-temperature delayed sintering technique in double-layer grain-boundary diffusion sintered Nd-Ce-Fe-B magnets 揭示低温延迟烧结技术在双层晶界扩散烧结Nd-Ce-Fe-B磁体中的作用

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-10-27 DOI: 10.1016/j.intermet.2025.109050

Chen Jiang , Jiajie Li , Zhixi Deng , Yue Huang , Qianjun Weng , Bowen Yang , Zheng Xiao , Munan Yang

To further improve the diffusion efficiency and reduce the cost of preparing high-performance Nd-Fe-B magnets, grain boundary diffusion of double-layer coated Nd-Ce-Fe-B sintered magnets was carried out by low temperature delayed (LTD) sintering. The results demonstrate that LTD-diffused magnets maintain a coercivity of 10 kOe at 150 °C, while achieving a remarkable coercivity increment of 12.97 kOe at room temperature. Microstructural analysis reveals that conventional diffusion converts triple junction phases into hexagonal Nd₂O₃, degrading coercivity by facilitating reversed domain nucleation, whereas LTD-diffusion maintains the original cubic Nd₂O₃ structure, thereby enhancing coercivity. The LTD sintering promotes the enrichment of Pr and Al elements at the grain boundaries, improving intergranular fluidity and thus creating favorable channels for the subsequent Tb diffusion. This not only increases the diffusion depth of Tb, but also improves the Tb concentration gradient and effectively improves the utilization efficiency of heavy rare earth. LTD technique offers a novel approach for fabricating high-performance Nd-Ce-Fe-B permanent magnets.

为了进一步提高扩散效率，降低制备高性能Nd-Fe-B磁体的成本，采用低温延迟烧结的方法对双层涂层Nd-Ce-Fe-B烧结磁体进行了晶界扩散。结果表明，在150°C时，ltd扩散磁体的矫顽力保持在10 kOe，而在室温下，矫顽力增加了12.97 kOe。显微组织分析表明，常规扩散将三结相转变为六边形Nd2O3，通过促进反畴成核而降低矫顽力，而有限扩散保持了Nd2O3的原始立方结构，从而提高了矫顽力。LTD烧结促进了Pr和Al元素在晶界的富集，提高了晶间流动性，从而为后续的Tb扩散创造了有利的通道。这不仅增加了Tb的扩散深度，而且提高了Tb浓度梯度，有效提高了重稀土的利用效率。该技术为制备高性能Nd-Ce-Fe-B永磁体提供了一种新的方法。

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引用次数: 0

Strengthening of nano-Y2O3 dispersed Al10Co25Cr8Fe15Ni36Ti6 based ODS-high entropy alloys for high temperature applications 纳米y2o3分散Al10Co25Cr8Fe15Ni36Ti6基ods -高熵合金高温强化研究

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics

Pub Date : 2025-10-27 DOI: 10.1016/j.intermet.2025.109046

Tukesh Ram Sahu, Subhas Ganguly, Sudip K. Sinha

In this study, Y₂O₃-reinforced Al₁₀Co₂₅Cr₈Fe₁₅Ni₃₆Ti₆ high entropy alloys (HEAs) were fabricated using mechanical alloying (MA) followed by spark plasma sintering (SPS). Following 30 h of milling, the phase composition of all four alloys results in the formation of a face-centered cubic (FCC) structure in addition to a body-centered cubic (BCC) solid solution structure. After consolidation via SPS at 900 °C, the presence of the FCC and Ni-Ti phases was detected in all alloys. Additionally, a minor garnet phase (Cr₂Fe₁₅Y₂) was identified in the alloys incorporating yttria (1, 2, 3 wt%). Analysis using X-ray diffraction (XRD) and High-Resolution Transmission Electron Microscopy (HR-TEM) indicates that the addition of Yttria nanoparticles restricts the grain growth of matrix alloys during SPS. The average grain size for alloys with 0 and 3 wt% Y₂O₃ was 280 nm–112 nm, respectively. The Y₂O₃-dispersed alloys demonstrated enhanced hardness and yield strength, recorded at 750 ± 7 H V and 1045 ± 13 MPa, respectively, for the 3 wt% Y₂O₃ dispersed alloy system. Notably, the novelty of these alloys lies in their microstructure, featuring a uniform distribution of Cr₂Fe₁₅Y₂ particles. The specific heat capacity of the composite increased with higher Y₂O₃ content. Thermal conductivity and diffusivity decreased with increasing Y₂O₃ content up to 2 wt%, but both properties exhibited a significant increase at 3 wt%, surpassing those at 1 and 2 wt%. This enhancement at 3 wt% Y₂O₃ suggests improved thermal transport properties, making this composition promising for high-temperature applications.

采用机械合金化（MA）和放电等离子烧结（SPS）制备了y2o3增强Al10Co25Cr8Fe15Ni36Ti6高熵合金（HEAs）。铣削30小时后，四种合金的相组成除形成体心立方（BCC）固溶结构外，还形成面心立方（FCC）结构。在900°C的SPS固结后，所有合金中都检测到FCC和Ni-Ti相的存在。此外，在含钇（1,2,3 wt%）的合金中发现了少量石榴石相（Cr2Fe15Y2）。x射线衍射（XRD）和高分辨率透射电镜（HR-TEM）分析表明，纳米钇的加入限制了SPS过程中基体合金的晶粒生长。Y2O3含量为0 wt%和3 wt%的合金的平均晶粒尺寸分别为280 nm ~ 112 nm。Y2O3分散合金的硬度和屈服强度分别为750±7 H V和1045±13 MPa。值得注意的是，这些合金的新颖之处在于它们的微观结构，具有均匀分布的Cr2Fe15Y2颗粒。随着Y2O3含量的增加，复合材料的比热容增大。当Y2O3含量增加到2 wt%时，导热系数和扩散系数下降，但当Y2O3含量增加到3 wt%时，导热系数和扩散系数显著增加，超过了1 wt%和2 wt%时的导热系数和扩散系数。在3 wt%的Y2O3下，这种增强表明热传递性能得到改善，使这种组合物在高温应用中有前景。

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引用次数: 0