International Journal of Refractory Metals & Hard Materials最新文献_第6页

Effect of Co doping on high-temperature deformation behavior and dynamic recrystallization mechanism of 93 W-Ni-Fe alloy Co掺杂对93 W-Ni-Fe合金高温变形行为及动态再结晶机理的影响

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-10 DOI: 10.1016/j.ijrmhm.2025.107605

Haonan Wu , Jianlei Yang , Huan Li , Wei Huang , Yang yu , Wencong Zhang

To address the issues of high ductile-brittle transition temperature (DBTT) and poor hot workability of tungsten alloys, this study investigates the effect of Co doping on the high-temperature deformation behavior and dynamic recrystallization (DRX) mechanism of 93 W-Ni-Fe alloys fabricated by liquid-phase sintering. Two alloy systems, 93 W-4.9Ni-2.1Fe and 93 W-4.9Ni-1.6Fe-0.5Co, were subjected to hot compression tests under deformation temperatures of 900–1300 °C and strain rates of 0.001–10s⁻¹. True stress-true strain curves were obtained, and microstructural evolution was characterized using EBSD and TEM.

The results show that at the same temperature and strain rate, 93 W-0.5Co exhibits a more significant softening trend than 93 W-0Co, as trace Co reduces dislocation energy and promotes dislocation movement. Based on the hyperbolic sine Arrhenius model, constitutive equations for the two alloys were established and the thermal processing map based on the dynamic material model (DMM) was constructed. EBSD and TEM analyses reveal a dual role of Co in regulating DRX: under low-temperature and high-strain-rate conditions, Co segregates inside tungsten particles to form dislocation pinning sites, hindering dislocation slip and annihilation, thereby inhibiting DRX and resulting in higher LAGB proportion and KAM value in 93 W-0.5Co. Under high-temperature and low-strain-rate conditions, Co acts as heterogeneous nucleation cores for recrystallization, reducing grain boundary energy and activation energy for dislocation movement, thus promoting DRX—93 W-0.5Co achieves a higher recrystallization fraction (56.7 % for GOS < 2 %) than 93 W-0Co (44.7 %). This study provides a theoretical basis for the optimal design of hot working processes for Co-strengthened tungsten alloys.

针对钨合金高韧脆转变温度（DBTT）和热加工性能差的问题，研究了Co掺杂对93种液相烧结W-Ni-Fe合金高温变形行为和动态再结晶（DRX）机制的影响。对93 W-4.9Ni-2.1Fe和93 W-4.9Ni-1.6Fe-0.5Co两种合金体系进行了热压缩试验，变形温度为900 ~ 1300℃，应变速率为0.001 ~ 10s−1。获得了真应力-真应变曲线，并利用EBSD和TEM对其微观组织演变进行了表征。结果表明：在相同温度和应变速率下，93 W-0.5Co比93 W-0Co表现出更明显的软化趋势，这是由于微量Co降低了位错能，促进了位错运动；基于双曲正弦Arrhenius模型，建立了两种合金的本构方程，构建了基于动态材料模型（DMM）的热加工图。EBSD和TEM分析揭示了Co在调控DRX中的双重作用：在低温和高应变速率条件下，Co在钨颗粒内部偏析形成位错钉住位点，阻碍位错滑移和湮灭，从而抑制DRX，导致93 W-0.5Co中LAGB比例和KAM值较高。在高温低应变速率条件下，Co作为非均相成核核进行再结晶，降低了晶界能和位错移动的活化能，从而促进DRX-93 W-0.5Co的再结晶率（GOS <； 2 %为56.7%）高于93 W-0Co（44.7%）。该研究为共强化钨合金热加工工艺的优化设计提供了理论依据。

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引用次数: 0

Preparation and characterization of WC-based cemented carbides with added V2O5 and Cr2O3 through spark plasma sintering 添加V2O5和Cr2O3的wc基硬质合金的火花等离子烧结制备及表征

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-09 DOI: 10.1016/j.ijrmhm.2025.107606

Yongkang Ma, Zhiwei Zhao, Wanzhen Qi, Qiujun Hu, Shijie Zhang, Xiaomiao Zhao, Shun Wang, Tongqi Shao, Jingke Wang

This study employs Spark Plasma Sintering (SPS) combined with in-situ carbothermic reduction to explore the impact of vanadium pentoxide (V₂O₅) and chromium oxide (Cr₂O₃) on the microstructure, phase composition, and mechanical properties of WC-based cemented carbides. Nanoscale WO₃, Co powder, carbon black, V₂O₅, and Cr₂O₃ were used as raw materials. In-situ synthesis of WC, V₈C₇, and Cr₃C₂, along with alloy densification, was successfully achieved within the SPS furnace. Experimental results indicate that the carbothermic reduction reaction reaches near completion at approximately 1200 °C. Under the conditions of 0.6 wt% composite grain growth inhibitors(CGGIs), a sintering temperature of 1400 °C, a dwell time of 8 min, and a pressure of 30 MPa, the resulting samples displayed a uniform microstructure and exhibited superior mechanical properties, with Vickers hardness of 2163.8 HV, fracture toughness of 9.9 MPa·m^1/2, and density of 14.45 g/cm³. The carbothermic reduction process of WO₃, V₂O₅, and Cr₂O₃ was simulated using HSC Chemistry software. The simulation results showed that the reduction of WO₃ was complete at the experimental temperature, while V₂O₅ and Cr₂O₃ only underwent partial reduction at higher temperatures. However, this partial reduction did not notably affect the preparation of the CGGIs or their contribution to the performance enhancement of the cemented carbide. The innovation of this study lies in the introduction of composite inhibitors, such as V₂O₅ and Cr₂O₃, which enhance the crack propagation path and significantly improve fracture toughness. This approach provides a novel method for optimizing the microstructure and performance of WC-based cemented carbides, offering both significant academic value and practical application potential.

本研究采用火花等离子烧结（SPS）结合原位碳热还原，探索五氧化二钒（V₂O₅）和氧化铬（Cr₂O₃）对wc基硬质合金微观结构、相组成和力学性能的影响。以纳米WO₃、Co粉、炭黑、V₂O₅、Cr₂O₃为原料。在SPS炉内成功地原位合成了WC、V₈C₇和Cr₃C₂，并实现了合金致密化。实验结果表明，碳热还原反应在1200℃左右接近完成。在添加量为0.6 wt%的复合晶粒生长抑制剂（CGGIs）、烧结温度为1400℃、保温时间为8 min、压力为30 MPa的条件下，得到的样品显微组织均匀，力学性能优异，维氏硬度为2163.8 HV，断裂韧性为9.9 MPa·m1/2，密度为14.45 g/cm3。利用HSC化学软件模拟了WO₃、V₂O₅和Cr₂O₃的碳热还原过程。模拟结果表明，WO₃在实验温度下完全还原，而V₂O₅和Cr₂O₃在较高温度下只进行了部分还原。然而，这种部分还原并没有显著影响CGGIs的制备或它们对硬质合金性能增强的贡献。本研究的创新之处在于引入了V₂O₅和Cr₂O₃等复合抑制剂，增强了裂纹扩展路径，显著提高了断裂韧性。该方法为优化wc基硬质合金的微观结构和性能提供了一种新的方法，具有重要的学术价值和实际应用潜力。

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引用次数: 0

Study on efficient electrolytic Co removal and structural properties of PDC via complexing agent regulation 络合剂调控对PDC高效电解除Co及结构性能的影响

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-09 DOI: 10.1016/j.ijrmhm.2025.107618

Houzhen Chen , Fuming Deng , Xiaotian Xing , Miao Gu , Jing Duo , Zhenhai Guo , Zhangjie Ye , Wenli Deng , Ziyi Liu , Qiang Chen , Yefei Zhang , Lei Zhang

In order to minimize the influence of metallic Co on the structural properties of polycrystalline diamond compact (PDC), this study employed an efficient electrolytic Co removal process to investigate the mechanism of complexing agents—Glycine (Gly), Citric Acid (CA), Tartaric Acid (TA), and Ethylene Diamine Tetraacetic Acid (EDTA)—in the electrolytic Co removal from PDC. The results show that Gly performed significantly better than CA, TA, and EDTA in Co removal from PDC. At the Gly concentration of 0.08 mol/L, the Co removal depth and Co removal rate reached 635 μm and 90.77 %, respectively, after 4 h of electrolysis. This significantly improves the efficiency of Co removal and enhances the abrasion ratio of PDC. Furthermore, Gly effectively relieved internal stresses within PDC and formed interconnected pore structures between diamond particles. These changes reduced the risk of delamination and cracking caused by residual stresses, thereby enhancing the service reliability of the material.

为了最大限度地减少金属Co对聚晶金刚石（PDC）结构性能的影响，本研究采用高效的电解除Co工艺，研究络合剂甘氨酸（Gly）、柠檬酸（CA）、酒石酸（TA）和乙二胺四乙酸（EDTA）在PDC中电解除Co的作用机理。结果表明，Gly对PDC中Co的去除效果明显优于CA、TA和EDTA。当Gly浓度为0.08 mol/L时，电解4 h后Co的去除率和深度分别达到635 μm和90.77%。这大大提高了Co的去除效率，提高了PDC的磨损比。此外，Gly有效地缓解了PDC内部的内应力，并在金刚石颗粒之间形成相互连接的孔隙结构。这些变化减少了由残余应力引起的分层和开裂的风险，从而提高了材料的使用可靠性。

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引用次数: 0

Microstructural and mechanical property enhancement in a low-co cemented carbide via a cold isostatic pressing-assisted binder jetting route 采用冷等静压辅助粘结剂喷射工艺提高低钴硬质合金的显微组织和力学性能

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-09 DOI: 10.1016/j.ijrmhm.2025.107620

Dezhi He , Honghua Hu , Rui Li , Yanxun Liang , Wei Duan , Xin Deng , Qingwei Jiang , Wenjun Tan , Fangxi Cheng , Fujian Guo

Binder jetting (BJ) stands as one of the most promising additive manufacturing techniques for cemented carbides. However, its high energy consumption, coupled with technical bottlenecks in microstructure defect control and density enhancement, has rarely enabled successful fabrication of carbides with cobalt (Co) contents below 10 wt%.

Here, we pioneer the production of a special low-Co cemented carbide (WC-6.5 %Co) using low-cost, low-energy-input carbide granules. By incorporating cold isostatic pressing (CIP), we achieved a significant improvement in green-to-brown-to-sintered density. For BJ-printed green carbide components, we developed a CIP-debinding-CIP process that markedly increases linear/volumetric shrinkage of green parts—thereby substantially reducing shrinkage during sintering and enabling superior dimensional/geometric accuracy control.

This CIP-debinding-CIP process yielded a sintered relative density of 99.5 %, effectively eliminating sintering defects such as pores, Co pools, and abnormally large WC grains, while producing a more homogeneous microstructure. Furthermore, the process significantly enhanced the mechanical properties of BJ-fabricated WC-6.5Co carbide: Vickers hardness reached 2103 HV30, transverse rupture strength (TRS) hit 1838 MPa, and fracture toughness reached 7.38 MPa·m¹/(Kai et al., 2023 [2]⁾.

Our study overcomes the current bottleneck in BJ processing of low-Co carbides and introduces a new paradigm: using low-cost, low-energy-input feedstock carbide powders for BJ. This approach substantially improves energy efficiency and reduces fabrication costs for additive manufacturing of cemented carbides.

粘结剂喷射（BJ）是最有前途的硬质合金增材制造技术之一。然而，它的高能耗，加上在微观结构缺陷控制和密度增强方面的技术瓶颈，很少能成功制造钴（Co）含量低于10 wt%的碳化物。在这里，我们率先生产一种特殊的低Co硬质合金（wc - 6.5% Co），使用低成本，低能量投入的硬质合金颗粒。通过结合冷等静压（CIP），我们实现了绿色到棕色到烧结密度的显着改善。对于bj印刷的绿色碳化物组件，我们开发了cip -脱脂- cip工艺，显着增加了绿色部件的线性/体积收缩率，从而大大减少了烧结过程中的收缩率，并实现了卓越的尺寸/几何精度控制。cip -脱脂- cip工艺的烧结相对密度为99.5%，有效地消除了气孔、Co池和异常大的WC晶粒等烧结缺陷，同时产生了更均匀的微观结构。此外，该工艺还显著提高了bj制备的WC-6.5Co碳化物的力学性能：维氏硬度达到2103 HV30，横向断裂强度（TRS）达到1838 MPa，断裂韧性达到7.38 MPa·m1/(Kai et al., 2023[2])。我们的研究克服了目前BJ加工低co碳化物的瓶颈，并引入了一种新的范例：使用低成本，低能量投入的硬质合金粉末作为BJ的原料。这种方法大大提高了能源效率，降低了硬质合金增材制造的制造成本。

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引用次数: 0

Development of a W-Cr-C tungsten alloy for synergistic printability and performance through laser powder bed fusion additive manufacturing 采用激光粉末床熔融增材制造技术研制具有协同印刷性能和增效性能的钨铬钨合金

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-09 DOI: 10.1016/j.ijrmhm.2025.107610

Prithvi Dev Awasthi , Priyanka Agrawal , Amit Kumar Singh , Aishani Sharma , Fredrick N. Michael , Rajiv S. Mishra

Current research efforts are exploring experimental techniques to enable additive manufacturing of traditionally “unprintable” refractory tungsten (W) alloys. These efforts often rely on parametric studies and design of experiments, which, while effective, tend to be both time-consuming and costly. As laser powder bed fusion additive manufacturing (L-PBF AM) continues to evolve rapidly for structural applications, there is a growing need for high-throughput, cost-effective, and computationally guided approaches to design printable, crack-free, and dense W alloys. This study presents a combined computational-experimental methodology for developing a novel W alloy tailored for L-PBF AM. By integrating CALPHAD (CALculation of PHAse Diagrams), the Scheil-Gulliver solidification model, and heat transfer material flow modeling, a W-based alloy incorporating chromium and carbon was designed. The alloy exhibited improved printability, achieving a solidus temperature of approximately 1886 K and a melting point near 3250 K. This composition enables the production of crack-free and nearly pore-free builds, with a relative density exceeding 99 %. The print demonstrated superior compressive strength of 1344 MPa and hardness in the range of 550–750 HV, owing to the good printability and the carbides formed.

目前的研究工作正在探索实验技术，以实现传统上“不可打印”的耐火钨(W)合金的增材制造。这些努力往往依赖于参数化研究和实验设计，虽然有效，但往往既耗时又昂贵。随着激光粉末床熔融增材制造（L-PBF AM）在结构应用领域的快速发展，对高通量、高成本效益和计算指导方法的需求不断增长，以设计可打印、无裂纹和致密的W合金。本研究提出了一种结合计算和实验的方法来开发一种适合L-PBF AM的新型W合金。结合相图计算（CALPHAD）、Scheil-Gulliver凝固模型和传热材料流模型，设计了一种含铬碳的w基合金。该合金的可印刷性得到了改善，其固相温度约为1886 K，熔点接近3250 K。这种成分使生产无裂纹和几乎无孔的建筑，相对密度超过99%。由于良好的印刷适性和形成的碳化物，印品的抗压强度达到1344 MPa，硬度在550 ~ 750 HV之间。

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引用次数: 0

Development of complex concentrated alloys binders for Co-free cemented WC composites 无钴硬质合金复合材料用复合浓缩合金粘结剂的研制

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-08 DOI: 10.1016/j.ijrmhm.2025.107604

Tiago Silva, Alexandre Bastos, Augusto Lopes

Cemented carbides such as WC–Co are widely used in industrial applications due to their excellent combination of properties, such as hardness, fracture toughness and wear resistance. However, in recent years, there has been increasing interest in partially or fully replacing cobalt as a binder because of concerns regarding its toxicity, price volatility and relatively poor corrosion resistance. One promising alternative is the use of complex concentrated alloys (CCAs), which have been identified in several studies as potential substitutes for Co. In this work, two CCAs (designated CCA1 and CCA2) were prepared and used as binders to produce Co-free cemented WC composites by pressureless sintering.

The WC-CCA1 samples achieved a relative density above 95 % and hardness comparable to that of WC–Co. However, the presence of Al-rich oxides and η-carbide phases contributed to a significant reduction in fracture toughness compared with that of conventional WC–Co composites. Based on these results and thermodynamic calculations, a modified binder (CCA2) was developed and tested. The samples prepared with CCA2 exhibited relative densities between 88.9 % and 92.8 % (depending on the binder fraction and initial WC particle size) and showed microstructures consisting of WC grains uniformly surrounded by an FCC phase. No secondary phases were detected and samples exhibiting hardness-fracture toughness combinations within the range reported for WC composites prepared with Co or other alternative binders were obtained. Moreover, a significant improvement in corrosion resistance was observed compared with WC–Co composites.

WC-Co等硬质合金由于其优异的综合性能，如硬度、断裂韧性和耐磨性，在工业应用中得到广泛应用。然而，近年来，由于担心钴的毒性、价格波动和相对较差的耐腐蚀性，人们对部分或完全取代钴作为粘合剂的兴趣越来越大。一种很有前途的替代方法是使用复合浓缩合金（CCAs），在几项研究中，它已被确定为Co的潜在替代品。在这项工作中，制备了两种CCAs（指定为CCA1和CCA2），并将其用作粘合剂，通过无压烧结生产无Co硬质合金复合材料。WC-CCA1样品的相对密度在95%以上，硬度与WC-Co相当。然而，与常规WC-Co复合材料相比，富al氧化物和η-碳化物相的存在导致其断裂韧性显著降低。基于这些结果和热力学计算，开发并测试了一种改性粘合剂（CCA2）。用CCA2制备的样品的相对密度在88.9%到92.8%之间（取决于粘合剂含量和初始WC粒度），并显示出由FCC相均匀包围的WC颗粒组成的微观结构。没有检测到二次相，并且样品的硬度-断裂韧性组合在用Co或其他替代粘合剂制备的WC复合材料的范围内。此外，与WC-Co复合材料相比，其耐腐蚀性能显著提高。

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引用次数: 0

Exploring nucleation mechanisms in the hydrogen reduction of MoO2 to Mo 探讨MoO2氢还原成Mo的成核机制

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-08 DOI: 10.1016/j.ijrmhm.2025.107615

S. Rainer , M.-G. Willinger , E. Willinger , M. O'Sullivan , H. Huppertz

The nucleation of various MoO₂ starting materials was investigated on a laboratory scale during the second reduction step from MoO₂ to Mo of the two-step reduction process from MoO₃ to Mo. It was found that a certain proportion of γ-Mo₄O₁₁ or a higher potassium content in the MoO₂ samples as well as the addition of water to the hydrogen gas stream led to a shift from the pseudomorphic transformation towards the CVT process at a low reduction temperature of 900 °C. Not only spherical/polyhedral Mo nuclei but also rod-shaped nuclei were detected for the first time using the γ-Mo₄O₁₁ containing MoO₂ starting material after a short reduction time and subsequent cooling in Ar gas flow. The influence of an increased potassium content in the γ-Mo₄O₁₁ containing MoO₂ samples on the nucleation was also investigated. Additionally, a mechanism for the formation of the rod-shaped nuclei is proposed.

各种MoO2开始的成核材料研究实验室规模的减少在第二步从MoO2密苏里州的两步还原法从MoO3密苏里州发现一定比例的γ-Mo4O11 MoO2样本或高钾含量以及加入的水到氢气流导致的假晶转变对CVT过程减少低的温度为900°C。用含有MoO2的γ-Mo4O11作为起始材料，经过短时间还原和氩气冷却后，首次检测到球形/多面体Mo核和棒状Mo核。研究了含MoO2的γ-Mo4O11样品中钾含量的增加对其成核的影响。此外，还提出了棒状核形成的机制。

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引用次数: 0

Insights into the evolution of microstructures and mechanical properties of tungsten‑lanthanum alloy core wires processed by drawing 钨镧合金拉丝芯线显微组织和力学性能演变的研究

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-08 DOI: 10.1016/j.ijrmhm.2025.107609

Dezhi Wang, Zixuan Tang, Ye Gao, Xin Li, Zhenchuan Li, Zhuangzhi Wu

To produce ultra-thin photovoltaic silicon wafers, WLa alloys are fabricated through powder metallurgy and plastic deformation methods, and the drawing process plays a crucial role in determining the final ultimate performances. In this work, the impact of drawing deformation parameters on the evolution of microstructure and mechanical properties in WLa wires were explored. It is found that increasing drawing strain promotes the <110> orientation parallel to drawing direction (DD), and the α-fiber texture is formed as the drawing strain increases to 1.86. In addition, the geometric dynamic recrystallization (GDRX) that occurs during the drawing process leads to dynamic grain refinement. The ultimate tensile strength (UTS) of WLa wires is enhanced with increased drawing strains, along with the transition of fracture modes from brittle to ductile behavior. The strengthening mechanism primarily involves grain refinement strengthening, followed by dislocation strengthening and second-phase strengthening. This work provides deeper insight into the structure-property relationship governing WLa wires during the drawing process.

为了生产超薄光伏硅片，采用粉末冶金和塑性变形的方法制备WLa合金，其中拉伸工艺对最终的极限性能起着至关重要的作用。研究了拉伸变形参数对WLa丝组织和力学性能演变的影响。结果表明，增大拉伸应变促进了平行于拉伸方向的< 110 >取向（DD），拉伸应变增大到1.86时α-纤维织构形成。此外，在拉伸过程中发生的几何动态再结晶（GDRX）导致动态晶粒细化。WLa钢丝的极限抗拉强度（UTS）随着拉伸应变的增加以及断裂模式从脆性向延性的转变而提高。强化机制主要是晶粒细化强化，其次是位错强化和第二相强化。这项工作为在绘图过程中控制WLa导线的结构-性能关系提供了更深入的见解。

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引用次数: 0

Mechanical performance of cold isostatic pressed W-6Ni-4Cu alloy with graphene reinforcements 石墨烯增强W-6Ni-4Cu合金冷等静压力学性能研究

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-08 DOI: 10.1016/j.ijrmhm.2025.107616

M. Kapousidou , T. Galvin , E. Jimenez-Melero

We have assessed the manufacturability and impact of adding graphene platelets in contents of x = 0, 0.01, 0.05, 0.1 wt.% to W-6Ni-4Cu as a model ‘ductile phase toughened’ tungsten heavy alloy (WHA). These alloys are potential candidates for future nuclear technologies and other structural applications in high-temperature radiation environments. Graphene additions were studied as potential reinforcement and to increase the interface density for mechanical and radiation tolerance of the alloy. The materials were produced successfully by cold isostatic pressing of the pre-mixed powders at a compaction pressure of 140 MPa, followed by liquid phase sintering at 1450–1500 °C under reducing 75% H₂/ 25% N₂ atmosphere. The graphene platelets are located at the Ni/Cu matrix-W grain and W-W grain interfaces. The material's density and surface roughness degrade when increasing the graphene content beyond 0.05 wt.%. This is coupled with a sharp reduction in tensile strength and elongation for 0.10 wt.% graphene, whereas those properties undergo an overall increasing trend with graphene content for x ≤ 0.05 wt.%. During tensile deformation of W-6Ni-4Cu (i.e. x = 0), strain localizes primarily in the ductile Ni/Cu matrix and at the matrix-W and W-W interfaces, with crack formation observed at W-W interfaces. However, graphene platelets enhance the load transfer from the matrix to the W grains, and also from grain to grain, therefore promoting a higher degree of cleavage inside the W grains. Graphene additions and cold isostatic pressing offer an avenue to enhance the WHA performance for applications in structures under ever demanding service environments.

我们评估了在W-6Ni-4Cu中添加x = 0,0.01, 0.05, 0.1 wt.%含量的石墨烯薄片作为模型“韧性相增韧”钨重合金（WHA）的可制造性和影响。这些合金是未来核技术和高温辐射环境中其他结构应用的潜在候选者。研究了添加石墨烯作为潜在增强剂和增加界面密度以提高合金的机械和辐射容忍度。将预混合粉末在140 MPa的压实压力下进行冷等静压，然后在1450 ~ 1500℃的温度下，在75% H2/ 25% N2气氛下进行液相烧结，成功制备了该材料。石墨烯薄片位于Ni/Cu基体- w晶粒和W-W晶粒界面。当石墨烯含量超过0.05 wt.%时，材料的密度和表面粗糙度下降。当石墨烯含量为0.10 wt.%时，拉伸强度和伸长率会急剧下降，而当石墨烯含量为x≤0.05 wt.%时，这些性能总体上呈上升趋势。在W-6Ni-4Cu（即x = 0）拉伸变形过程中，应变主要集中在韧性Ni/Cu基体以及基体- w和W-W界面处，W-W界面处出现裂纹形成。然而，石墨烯薄片增强了载荷从基体到W晶粒的传递，以及从晶粒到晶粒的传递，从而促进了W晶粒内部更高程度的解理。石墨烯的添加和冷等静压为在苛刻的服务环境下的结构应用中提高WHA性能提供了一条途径。

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引用次数: 0

The stress concentration effect of La₂O₃ second-phase particles in molybdenum alloys with the dominant mechanisms La₂O₃第二相颗粒在钼合金中的应力集中效应具有主导机制

IF 4.6 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-08 DOI: 10.1016/j.ijrmhm.2025.107617

Shichen Wang , Junzhou Yang , Yongqiang Fang , Hairui Xing , Li Wang , Wenting Ye , Hua Wang , Caihong Chang , Kunming Pan , Ping Hu

This paper systematically investigates the effect of stress concentration induced by second-phase particles on the mechanical properties of molybdenum (Mo) alloys. Three types of Mo alloys were fabricated via powder metallurgy, and their flow behavior, hardness and morphology have been characterized. A stress concentration factor model has been established to quantitatively assess the effect of La₂O₃ second-phase particles on stress concentration. The stress concentration factor model developed considers three factors: the second-phase particle size r, the interparticle spacing a, and the grain size d. Pearson correlation analysis confirmed the above three variables are mutually independent. The analysis of the dominant factors influencing stress concentration reveals the influence order: r > a > d. The effect of different size ranges of r and a on stress concentration varies. Nano-scale second-phase particles (r<10³ nm) exhibit superior strengthening and toughening effects, while for micron-scale second-phase particles (10³ nm < r < 5 × 10⁴ nm), stress concentration can be mitigated by controlling grain coarsening and particle spacing. When r > 5 × 10³ nm, balancing the second-phase particle size and spacing to achieve a dispersed distribution is essential to reduce stress concentration and maintain a favorable strength-toughness balance.

本文系统地研究了第二相颗粒引起的应力集中对钼合金力学性能的影响。采用粉末冶金法制备了三种Mo合金，并对其流动性能、硬度和形貌进行了表征。建立了应力集中因子模型，定量评价了La2O3二相颗粒对应力集中的影响。建立的应力集中因子模型考虑了二相粒径r、粒间间距a和晶粒尺寸d三个因素，Pearson相关分析证实上述三个变量是相互独立的。对影响应力集中的主导因素进行分析，其影响顺序为：r >； a > d。r和a的不同尺寸范围对应力集中的影响是不同的。纳米级第二相颗粒（r<103 nm）表现出优异的强化和增韧效果，而对于微米级第二相颗粒（103 nm < r< 5 × 104 nm），可以通过控制晶粒粗化和颗粒间距来减轻应力集中。当r >； 5 × 103 nm时，平衡第二相粒径和间距以达到分散分布是降低应力集中和保持良好的强度-韧性平衡的必要条件。

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