International Journal of Refractory Metals & Hard Materials最新文献_第7页

Lightweight diamond/WC–Co composites achieve synergistic hardness-toughness enhancement via high-pressure sintering 轻质金刚石/ WC-Co复合材料通过高压烧结实现了硬度和韧性的协同增强

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-23 DOI: 10.1016/j.ijrmhm.2025.107637

Yinxing Su , Qian Li , Duanwei He , Jiawei Zhang

The widely recognized inverse correlation between hardness and toughness presents a major obstacle to achieving both properties simultaneously, particularly in cemented carbides. Diamond has been regarded as an ideal reinforcing phase for WC-Co composites due to its ultra-high hardness (which enhances overall composite hardness), high bulk modulus (which promotes crack deflection, blunting, and bifurcation thereby improving toughness), and low density (which enables lightweighting). However, under conventional sintering conditions, diamond undergoes severe graphitization, causing its strengthening effect to fail and leading to significant performance loss. In contrast, high-pressure high-temperature (HPHT) sintering fundamentally overcomes this issue: the applied high pressure stabilizes the diamond phase by elevating its graphitization temperature, while simultaneously enhancing interfacial bonding with the WC-Co matrix. By optimizing composition and sintering parameters, a WC-10 vol% Co-50 vol% diamond composite achieved near-full densification (99.02 % relative density), exhibiting high hardness (28.16 GPa), enhanced fracture toughness (14.68

MPa ∙ m^{1 / 2}

), good electrical conductivity (

8.36 \times 10^{- 5} Ω ∙ m

), for electrical discharge machining (EDM) capability, and a significantly reduced density of 8.81 g/cm³ (approximately 40 % lighter than conventional WC-Co). This unique composite provides an outstanding balance of performance and lightweight characteristics for advanced applications requiring high strength, toughness, and reduced weight.

人们普遍认为硬度和韧性之间的负相关关系是同时实现这两种性能的主要障碍，特别是在硬质合金中。金刚石被认为是WC-Co复合材料的理想增强相，因为它具有超高硬度（提高复合材料的整体硬度）、高体积模量（促进裂纹偏转、钝化和分叉，从而提高韧性）和低密度（实现轻量化）。然而，在常规烧结条件下，金刚石会发生严重的石墨化，导致其强化效果失效，性能损失显著。相比之下，高压高温烧结（HPHT）从根本上克服了这一问题：施加的高压通过提高石墨化温度来稳定金刚石相，同时增强了与WC-Co基体的界面结合。通过优化成分和烧结参数，WC-10 vol% Co-50 vol%金刚石复合材料实现了接近完全致密化（相对密度99.02%），具有高硬度（28.16 GPa），增强断裂韧性（14.68 MPa∙m1/2），良好的电导率（8.36×10−5Ω∙m），具有电火花加工（EDM）能力，并且密度显著降低至8.81 g/cm3（比常规WC-Co轻约40%）。这种独特的复合材料为需要高强度、高韧性和轻量化的先进应用提供了出色的性能和轻量化平衡。

{"title":"Lightweight diamond/WC–Co composites achieve synergistic hardness-toughness enhancement via high-pressure sintering","authors":"Yinxing Su , Qian Li , Duanwei He , Jiawei Zhang","doi":"10.1016/j.ijrmhm.2025.107637","DOIUrl":"10.1016/j.ijrmhm.2025.107637","url":null,"abstract":"<div><div>The widely recognized inverse correlation between hardness and toughness presents a major obstacle to achieving both properties simultaneously, particularly in cemented carbides. Diamond has been regarded as an ideal reinforcing phase for WC-Co composites due to its ultra-high hardness (which enhances overall composite hardness), high bulk modulus (which promotes crack deflection, blunting, and bifurcation thereby improving toughness), and low density (which enables lightweighting). However, under conventional sintering conditions, diamond undergoes severe graphitization, causing its strengthening effect to fail and leading to significant performance loss. In contrast, high-pressure high-temperature (HPHT) sintering fundamentally overcomes this issue: the applied high pressure stabilizes the diamond phase by elevating its graphitization temperature, while simultaneously enhancing interfacial bonding with the WC-Co matrix. By optimizing composition and sintering parameters, a WC-10 vol% Co-50 vol% diamond composite achieved near-full densification (99.02 % relative density), exhibiting high hardness (28.16 GPa), enhanced fracture toughness (14.68 <span><math><mi>MPa</mi><mo>∙</mo><msup><mi>m</mi><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math></span>), good electrical conductivity (<span><math><mn>8.36</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup><mspace></mspace><mi>Ω</mi><mo>∙</mo><mi>m</mi></math></span>), for electrical discharge machining (EDM) capability, and a significantly reduced density of 8.81 g/cm<sup>3</sup> (approximately 40 % lighter than conventional WC-Co). This unique composite provides an outstanding balance of performance and lightweight characteristics for advanced applications requiring high strength, toughness, and reduced weight.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107637"},"PeriodicalIF":4.6,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837168","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

Investigating into the mechanisms of high temperature strength of refractory high-entropy alloys 耐火高熵合金高温强度的机理研究

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-23 DOI: 10.1016/j.ijrmhm.2025.107640

Sai Anandhi Seetharaman, Soumyadipta Maiti, Ambesh Gupta, Beena Rai

The yield strength plateau of two BCC refractory high entropy alloys (RHEAs) – MoNbTaVW and MoNbTaW was examined through hybrid Monte Carlo and molecular dynamics (MC/MD) simulations. By analyzing atomic diffusivities derived from vacancy formation and migration energies around the edge dislocation cores, the number of critical atomic swaps were calculated at different temperatures. Using hybrid MC/MD simulations of these critical swaps, we demonstrate that above 1400 K, the stress required to move the dislocations gets saturated, indicating the effect of Dynamic Strain Ageing (DSA) via “cross core motion”. Further simulations on random solid solutions (0 MC swaps) revealed a similar plateau effect at the intermediate temperatures. This was attributed to the additional athermal stress arising from lattice distortions due to solid solution strengthening. Our findings suggest that the yield strength plateau results from an interplay between the DSA-driven diffusion process and athermal stress. Specifically, the plateau emerges from DSA mechanisms in the presence of atomic diffusion, whereas in the absence of diffusion, it is governed by athermal statistical lattice distortions. This dual mechanism framework provides a comprehensive explanation for the experimentally observed Yield strength behavior in RHEAs at intermediate temperatures.

采用蒙特卡罗和分子动力学（MC/MD）模拟研究了两种BCC难熔高熵合金（MoNbTaVW和MoNbTaW）的屈服强度平台。通过分析由空位形成引起的原子扩散系数和边缘位错核心周围的迁移能，计算了不同温度下的临界原子交换次数。通过混合MC/MD模拟这些临界交换，我们证明在1400 K以上，移动位错所需的应力达到饱和，表明动态应变老化（DSA）通过“交叉核运动”的影响。对随机固溶体（0 MC交换）的进一步模拟表明，在中等温度下也存在类似的平台效应。这是由于固溶体强化引起的晶格畸变引起的额外非热应力。我们的研究结果表明，屈服强度平台是dsa驱动的扩散过程和非热应力相互作用的结果。具体来说，在原子扩散存在的情况下，平台从DSA机制中出现，而在没有扩散的情况下，它由非热统计晶格畸变控制。这种双重机制框架为实验观察到的中间温度下RHEAs的屈服强度行为提供了全面的解释。

{"title":"Investigating into the mechanisms of high temperature strength of refractory high-entropy alloys","authors":"Sai Anandhi Seetharaman, Soumyadipta Maiti, Ambesh Gupta, Beena Rai","doi":"10.1016/j.ijrmhm.2025.107640","DOIUrl":"10.1016/j.ijrmhm.2025.107640","url":null,"abstract":"<div><div>The yield strength plateau of two BCC refractory high entropy alloys (RHEAs) – MoNbTaVW and MoNbTaW was examined through hybrid Monte Carlo and molecular dynamics (MC/MD) simulations. By analyzing atomic diffusivities derived from vacancy formation and migration energies around the edge dislocation cores, the number of critical atomic swaps were calculated at different temperatures. Using hybrid MC/MD simulations of these critical swaps, we demonstrate that above 1400 K, the stress required to move the dislocations gets saturated, indicating the effect of Dynamic Strain Ageing (DSA) via “cross core motion”. Further simulations on random solid solutions (0 MC swaps) revealed a similar plateau effect at the intermediate temperatures. This was attributed to the additional athermal stress arising from lattice distortions due to solid solution strengthening. Our findings suggest that the yield strength plateau results from an interplay between the DSA-driven diffusion process and athermal stress. Specifically, the plateau emerges from DSA mechanisms in the presence of atomic diffusion, whereas in the absence of diffusion, it is governed by athermal statistical lattice distortions. This dual mechanism framework provides a comprehensive explanation for the experimentally observed Yield strength behavior in RHEAs at intermediate temperatures.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107640"},"PeriodicalIF":4.6,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837091","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

A novel strategy of high-entropy nitride coating for cemented carbide cutting tool: Preparation, microstructure, mechanical and wear properties 硬质合金刀具高熵氮化涂层的制备、显微组织、力学性能和磨损性能

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-22 DOI: 10.1016/j.ijrmhm.2025.107644

Keke Li, Wenting Shao, Ruilong Wen, Wei Yang, Shangkun Wu, Jian Chen

High-entropy nitrides (HENs) are emerging as next-generation protective coatings that offer superior performance over conventional nitrides on cutting tools. This study explores a new class of HEN coatings with the composition (AlTi_xNbCrZr)N (x = 0, 0.5, 1), alongside a conventional TiAlN coating, both deposited on cemented carbide substrates via magnetron sputtering. Comprehensive analyses were carried out to evaluate their microstructural characteristics, mechanical and wear properties. The results indicate that both TiAlN and (AlTi_xNbCrZr)N coatings exhibit a single-phase face-centered cubic (FCC) solid solution. Compared with the conventional TiAlN coating, HEN coatings exhibit significantly enhanced mechanical properties due to intensified Me-N covalent bonding and lattice distortion-induced energy barriers that impede dislocation motion and slip. As the Ti content increased, the (AlTi_xNbCrZr)N coatings displayed progressive improvements in mechanical performance, reaching a peak hardness of 46.06 GPa. This enhancement is consistent with the inverse Hall-Petch regime for sub-10 nm grain sizes, where grain coarsening enhances hardness by suppressing grain boundary sliding as the dominant deformation mechanism. In terms of wear resistance, the HEN coatings outperformed TiAlN, benefiting from solid solution strengthening driven by high entropy. Among (AlTi_xNbCrZr)N coatings, (AlTi_0.5NbCrZr)N demonstrates optimal wear resistance (wear rate: 4.18 × 10⁻⁸ mm³/N·m), attributed to balanced suppression of two failure pathways: (i) excessive abrasive particle formation from low-hardness coatings, and (ii) adhesive wear promoted by elevated Ti content through enhanced material adhesion at the ball-coating interface, leading to accelerated coating tearing failure. The dominant wear mechanisms were identified as adhesive wear and oxidative wear, with slight abrasive wear. These findings offer valuable insights and foundational data for advancing Ti alloy machining technologies.

高熵氮化物（HENs）正在成为新一代切削工具防护涂层，其性能优于传统氮化物。本研究探索了一类新的HEN涂层，其成分为（AlTixNbCrZr）N (x = 0,0.5, 1)，与传统的TiAlN涂层一起，通过磁控溅射沉积在硬质合金基体上。对其显微组织特征、力学性能和磨损性能进行了综合分析。结果表明：TiAlN和（AlTixNbCrZr）N涂层均表现为单相面心立方（FCC）固溶体；与传统的TiAlN涂层相比，HEN涂层的力学性能显著提高，这是由于Me-N共价键的增强和晶格畸变引起的能垒阻碍了位错运动和滑移。随着Ti含量的增加，（AlTixNbCrZr）N涂层的力学性能逐渐提高，硬度峰值达到46.06 GPa。这种增强与10 nm以下晶粒尺寸的逆Hall-Petch机制一致，晶粒粗化通过抑制晶界滑动作为主要变形机制来提高硬度。在耐磨性方面，HEN涂层优于TiAlN，受益于高熵驱动的固溶体强化。在（AlTixNbCrZr）N涂层中，（AlTi0.5NbCrZr）N涂层表现出最佳的耐磨性（磨损率为4.18 × 10−8 mm3/N·m），这是由于平衡抑制了两种失效途径：(1)低硬度涂层形成过多的磨粒；(2)升高的Ti含量通过增强材料在球-涂层界面的附着力而促进黏着磨损，从而加速涂层撕裂失效。主要的磨损机制是粘着磨损和氧化磨损，轻微的磨粒磨损。这些发现为推进钛合金加工技术提供了有价值的见解和基础数据。

{"title":"A novel strategy of high-entropy nitride coating for cemented carbide cutting tool: Preparation, microstructure, mechanical and wear properties","authors":"Keke Li, Wenting Shao, Ruilong Wen, Wei Yang, Shangkun Wu, Jian Chen","doi":"10.1016/j.ijrmhm.2025.107644","DOIUrl":"10.1016/j.ijrmhm.2025.107644","url":null,"abstract":"<div><div>High-entropy nitrides (HENs) are emerging as next-generation protective coatings that offer superior performance over conventional nitrides on cutting tools. This study explores a new class of HEN coatings with the composition (AlTi<sub>x</sub>NbCrZr)N (x = 0, 0.5, 1), alongside a conventional TiAlN coating, both deposited on cemented carbide substrates via magnetron sputtering. Comprehensive analyses were carried out to evaluate their microstructural characteristics, mechanical and wear properties. The results indicate that both TiAlN and (AlTi<sub>x</sub>NbCrZr)N coatings exhibit a single-phase face-centered cubic (FCC) solid solution. Compared with the conventional TiAlN coating, HEN coatings exhibit significantly enhanced mechanical properties due to intensified Me-N covalent bonding and lattice distortion-induced energy barriers that impede dislocation motion and slip. As the Ti content increased, the (AlTi<sub>x</sub>NbCrZr)N coatings displayed progressive improvements in mechanical performance, reaching a peak hardness of 46.06 GPa. This enhancement is consistent with the inverse Hall-Petch regime for sub-10 nm grain sizes, where grain coarsening enhances hardness by suppressing grain boundary sliding as the dominant deformation mechanism. In terms of wear resistance, the HEN coatings outperformed TiAlN, benefiting from solid solution strengthening driven by high entropy. Among (AlTi<sub>x</sub>NbCrZr)N coatings, (AlTi<sub>0.5</sub>NbCrZr)N demonstrates optimal wear resistance (wear rate: 4.18 × 10<sup>−8</sup> mm<sup>3</sup>/N·m), attributed to balanced suppression of two failure pathways: (i) excessive abrasive particle formation from low-hardness coatings, and (ii) adhesive wear promoted by elevated Ti content through enhanced material adhesion at the ball-coating interface, leading to accelerated coating tearing failure. The dominant wear mechanisms were identified as adhesive wear and oxidative wear, with slight abrasive wear. These findings offer valuable insights and foundational data for advancing Ti alloy machining technologies.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107644"},"PeriodicalIF":4.6,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837169","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

Optimization of mechanical properties in hybrid (TiCN-WC)/Co cermets prepared via spark plasma sintering 火花等离子烧结TiCN-WC /Co杂化陶瓷的力学性能优化

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-22 DOI: 10.1016/j.ijrmhm.2025.107642

Ali Fazili, Leila Nikzad, Mansour Razavi

This study presents a comprehensive investigation of the sintering behavior, microstructural evolution, and mechanical properties of (100-xTiCN-xWC)/Co composites fabricated via spark plasma sintering (SPS). Eleven compositions with varying TiCN and WC weight fractions (0–100 wt% WC) were prepared under optimized sintering conditions (1300–1450 °C, 20 MPa, 6 min). X-ray diffraction (XRD) and Rietveld refinement confirmed the retention of the original TiCN, WC, and Co phases without any detectable interdiffusion or secondary phase formation. All samples achieved excellent densification, with relative densities exceeding 98.5 %, demonstrating the effectiveness of SPS in producing fully dense composites.

Field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS) revealed homogeneous and pore-free microstructures with well-dispersed WC and TiCN phases and a continuous Co binder network. Increasing WC content enhanced sintering kinetics, reduced the shrinkage onset temperature by approximately 100 °C, and promoted uniform densification. Mechanical testing indicated strong compositional dependence of properties. The Vickers hardness (HV10) increased from 14.6 ± 0.53 GPa for TiCN/Co to a maximum of 20.9 ± 0.89 GPa at 60 wt% WC, before slightly declining at higher WC levels. Flexural strength improved steadily with WC addition, reaching 2216 ± 85 MPa for the WC/Co composite. Fracture toughness (K1C) exhibited a non-monotonic trend, decreasing to 9.3 ± 0.7 MPa·m^0.5 at 60 wt% WC and recovering to 16.1 ± 0.3 MPa·m^0.5 at 100 wt% WC. These findings demonstrate that combining TiCN and WC phases enables precise control over the balance between hardness, toughness, and strength. The hybrid composite with 60 wt% WC exhibited the optimal performance, establishing (TiCN-WC)/Co systems as promising candidates for advanced cutting and wear-resistant applications.

本文研究了放电等离子烧结（SPS）制备的(100-xTiCN-xWC)/Co复合材料的烧结行为、显微组织演变和力学性能。在优化的烧结条件（1300 ~ 1450℃，20 MPa, 6 min）下，制备了11种不同TiCN和WC重量分数（0 ~ 100 wt% WC）的复合材料。x射线衍射（XRD）和Rietveld细化证实了原始TiCN、WC和Co相的保留，没有任何可检测到的相互扩散或二次相的形成。所有样品均获得了优异的致密化，相对密度超过98.5%，证明了SPS在生产全致密复合材料方面的有效性。场发射扫描电镜（FESEM）和能量色散x射线能谱（EDS）显示了均匀无孔的微观结构，具有分散良好的WC和TiCN相和连续的Co结合物网络。WC含量的增加提高了烧结动力学，使收缩起始温度降低了约100℃，促进了致密化的均匀化。力学试验表明，性能对组分有很强的依赖性。当WC为60 wt%时，TiCN/Co的维氏硬度（HV10）从14.6±0.53 GPa上升到20.9±0.89 GPa，在WC水平较高时略有下降。WC的加入使WC/Co复合材料的抗弯强度稳步提高，达到2216±85 MPa。断裂韧性（K1C）呈现非单调趋势，在wt% WC时下降到9.3±0.7 MPa·m0.5，在wt% WC时恢复到16.1±0.3 MPa·m0.5。这些发现表明，结合TiCN和WC相可以精确控制硬度、韧性和强度之间的平衡。WC含量为60%的复合材料表现出最佳性能，使TiCN-WC /Co体系成为先进切削和耐磨应用的有希望的候选者。

{"title":"Optimization of mechanical properties in hybrid (TiCN-WC)/Co cermets prepared via spark plasma sintering","authors":"Ali Fazili, Leila Nikzad, Mansour Razavi","doi":"10.1016/j.ijrmhm.2025.107642","DOIUrl":"10.1016/j.ijrmhm.2025.107642","url":null,"abstract":"<div><div>This study presents a comprehensive investigation of the sintering behavior, microstructural evolution, and mechanical properties of (100-xTiCN-xWC)/Co composites fabricated via spark plasma sintering (SPS). Eleven compositions with varying TiCN and WC weight fractions (0–100 wt% WC) were prepared under optimized sintering conditions (1300–1450 °C, 20 MPa, 6 min). X-ray diffraction (XRD) and Rietveld refinement confirmed the retention of the original TiCN, WC, and Co phases without any detectable interdiffusion or secondary phase formation. All samples achieved excellent densification, with relative densities exceeding 98.5 %, demonstrating the effectiveness of SPS in producing fully dense composites.</div><div>Field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy (EDS) revealed homogeneous and pore-free microstructures with well-dispersed WC and TiCN phases and a continuous Co binder network. Increasing WC content enhanced sintering kinetics, reduced the shrinkage onset temperature by approximately 100 °C, and promoted uniform densification. Mechanical testing indicated strong compositional dependence of properties. The Vickers hardness (HV10) increased from 14.6 ± 0.53 GPa for TiCN/Co to a maximum of 20.9 ± 0.89 GPa at 60 wt% WC, before slightly declining at higher WC levels. Flexural strength improved steadily with WC addition, reaching 2216 ± 85 MPa for the WC/Co composite. Fracture toughness (K1C) exhibited a non-monotonic trend, decreasing to 9.3 ± 0.7 MPa·m<sup>0.5</sup> at 60 wt% WC and recovering to 16.1 ± 0.3 MPa·m<sup>0.5</sup> at 100 wt% WC. These findings demonstrate that combining TiCN and WC phases enables precise control over the balance between hardness, toughness, and strength. The hybrid composite with 60 wt% WC exhibited the optimal performance, establishing (TiCN-WC)/Co systems as promising candidates for advanced cutting and wear-resistant applications.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107642"},"PeriodicalIF":4.6,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837090","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

Microstructure and non-isothermal reduction behavior of ball-milled WO3-CuO powders in pure hydrogen atmosphere 纯氢气氛下球磨WO3-CuO粉末的微观结构及非等温还原行为

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-20 DOI: 10.1016/j.ijrmhm.2025.107632

Eui Seon Lee, Ji Young Kim, Sung-Tag Oh

The microstructural characteristics and hydrogen reduction behavior of W and W-10 wt% Cu powders have been investigated. These powders are synthesized by ball milling and hydrogen reduction of WO₃ and WO₃–CuO. The reduction behavior of oxide powders under non-isothermal condition is examined using thermogravimetric analysis at varing heating rates in pure hydrogen atmosphere. After milling for 5 h and hydrogen reduction at 800 °C, the oxide powders were completely converted to W and WCu with an average particle size of about 300 nm. TEM analysis for the reduced WCu powder revealed that nano-sized Cu particles were located on the surface of the coarse W particles. The activation energies for the reduction of pure WO₃ and WO₃–CuO, estimated by the slope of the Kissinger plot, were measured as 58.9–123.3 kJ/mol depending on reduction steps. In the reduction process of WO₂ to W, the WO₃-CuO powder mixture exhibited lower activation energy compared to pure WO₃ powder. The decrease in activation energy is attributed to the role of pre-reduced Cu particles as nucleation sites for W during the reduction process via chemical vapor transport of WO₂(OH)₂.

研究了W和W- 10wt % Cu粉末的显微组织特征和氢还原行为。采用球磨和氢还原法制备了WO3和WO3 - cuo粉末。用热重法研究了在纯氢气氛中不同升温速率下氧化粉末在非等温条件下的还原行为。经过5 h的磨矿和800℃的氢还原，氧化物粉末完全转化为W和WCu，平均粒径约为300 nm。对还原后的WCu粉末的TEM分析表明，纳米级的Cu颗粒位于粗W颗粒的表面。根据Kissinger曲线的斜率估计，不同还原步骤，纯WO3和WO3 - cuo的还原活化能为58.9 ~ 123.3 kJ/mol。在WO2还原为W的过程中，WO3- cuo粉末混合物的活化能比纯WO3粉末低。活化能的降低是由于在WO2(OH)2的化学气运还原过程中，预还原的Cu粒子作为W的成核位点的作用。

{"title":"Microstructure and non-isothermal reduction behavior of ball-milled WO3-CuO powders in pure hydrogen atmosphere","authors":"Eui Seon Lee, Ji Young Kim, Sung-Tag Oh","doi":"10.1016/j.ijrmhm.2025.107632","DOIUrl":"10.1016/j.ijrmhm.2025.107632","url":null,"abstract":"<div><div>The microstructural characteristics and hydrogen reduction behavior of W and W-10 wt% Cu powders have been investigated. These powders are synthesized by ball milling and hydrogen reduction of WO<sub>3</sub> and WO<sub>3</sub>–CuO. The reduction behavior of oxide powders under non-isothermal condition is examined using thermogravimetric analysis at varing heating rates in pure hydrogen atmosphere. After milling for 5 h and hydrogen reduction at 800 °C, the oxide powders were completely converted to W and W<img>Cu with an average particle size of about 300 nm. TEM analysis for the reduced W<img>Cu powder revealed that nano-sized Cu particles were located on the surface of the coarse W particles. The activation energies for the reduction of pure WO<sub>3</sub> and WO<sub>3</sub>–CuO, estimated by the slope of the Kissinger plot, were measured as 58.9–123.3 kJ/mol depending on reduction steps. In the reduction process of WO<sub>2</sub> to W, the WO<sub>3</sub>-CuO powder mixture exhibited lower activation energy compared to pure WO<sub>3</sub> powder. The decrease in activation energy is attributed to the role of pre-reduced Cu particles as nucleation sites for W during the reduction process via chemical vapor transport of WO<sub>2</sub>(OH)<sub>2</sub>.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107632"},"PeriodicalIF":4.6,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784589","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

Aqueous-phase synthesis of hafnium carbonitride precursors via bidentate ligand coordination 双齿配位法水相合成碳氮化铪前驱体

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-18 DOI: 10.1016/j.ijrmhm.2025.107633

Wooseok Jin , Chanseok Moon , Dong-Geun Shin , Jaehan Jung , Doh Hyung Riu

The rapid advancement of hypersonic aerospace technologies greatly demands the development of ultra-high temperature ceramics. Among them, hafnium-based ceramics such as hafnium carbide (HfC) and hafnium carbonitride (HfC_xN_1-x) are promising candidates due to their high melting points, hardness, and excellent ablation resistance. However, the design and control of polymer-derived precursors for hafnium carbonitride has not been fully researched. Here, we report an aqueous-phase synthesis of HfC_xN_1-x precursor using ethylenediamine (EDA) in combination with cellulose. EDA, a bidentate ligand, coordinates with Hf as well as cellulose, thus forming polymeric networks and facilitating the generation of an amorphous carbon shell during heat treatment. Notably, induced HfN bonds promotes the intermediate formation of Hf₂ON₂ and HfN phases hence lowering the energy barrier for HfC_xN_1-x phase evolution. Finally, HfC_xN_1-x nanoparticles heat-treated at 1400 °C were sintered at 2100 °C, confirming the sintering feasibility of the aqueous-phase prepared precursors.

高超声速航天技术的飞速发展对超高温陶瓷的发展提出了巨大的要求。其中，碳化铪（HfC）和碳氮化铪（HfCxN1-x）等铪基陶瓷因其高熔点、硬度和优异的抗烧蚀性而成为有希望的候选材料。然而，聚合物衍生碳氮化铪前驱体的设计和控制尚未得到充分的研究。在这里，我们报道了用乙二胺（EDA）与纤维素相结合的水相合成HfCxN1-x前体。EDA是一种双齿配体，与Hf和纤维素配位，从而形成聚合物网络，并促进在热处理过程中产生无定形碳壳。值得注意的是，诱导的HfN键促进了Hf2ON2和HfN相的中间形成，从而降低了HfCxN1-x相演化的能垒。最后，经1400℃热处理的HfCxN1-x纳米颗粒在2100℃下烧结，证实了水相制备前驱体烧结的可行性。

{"title":"Aqueous-phase synthesis of hafnium carbonitride precursors via bidentate ligand coordination","authors":"Wooseok Jin , Chanseok Moon , Dong-Geun Shin , Jaehan Jung , Doh Hyung Riu","doi":"10.1016/j.ijrmhm.2025.107633","DOIUrl":"10.1016/j.ijrmhm.2025.107633","url":null,"abstract":"<div><div>The rapid advancement of hypersonic aerospace technologies greatly demands the development of ultra-high temperature ceramics. Among them, hafnium-based ceramics such as hafnium carbide (HfC) and hafnium carbonitride (HfC<sub>x</sub>N<sub>1-x</sub>) are promising candidates due to their high melting points, hardness, and excellent ablation resistance. However, the design and control of polymer-derived precursors for hafnium carbonitride has not been fully researched. Here, we report an aqueous-phase synthesis of HfC<sub>x</sub>N<sub>1-x</sub> precursor using ethylenediamine (EDA) in combination with cellulose. EDA, a bidentate ligand, coordinates with Hf as well as cellulose, thus forming polymeric networks and facilitating the generation of an amorphous carbon shell during heat treatment. Notably, induced Hf<img>N bonds promotes the intermediate formation of Hf<sub>2</sub>ON<sub>2</sub> and HfN phases hence lowering the energy barrier for HfC<sub>x</sub>N<sub>1-x</sub> phase evolution. Finally, HfC<sub>x</sub>N<sub>1-x</sub> nanoparticles heat-treated at 1400 °C were sintered at 2100 °C, confirming the sintering feasibility of the aqueous-phase prepared precursors.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107633"},"PeriodicalIF":4.6,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784610","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

A new method for preparing ultrafine Mo2C by the CVD reaction of CO and gaseous MoO3: Parameter optimization and its formation mechanism CO与气态MoO3 CVD反应制备超细Mo2C的新方法：参数优化及其形成机理

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-18 DOI: 10.1016/j.ijrmhm.2025.107636

Lu Wang , Bing-Han Sun , Jian-Jun Yu , Jian-Li Li

In the work, the method of chemical vapor deposition reaction of CO and gaseous MoO₃ was proposed to prepare ultrafine Mo₂C. Different technologies, such as XRD, FESEM, TEM, laser particle size analysis and Brunauer-Emmett-Teller method, as well as thermodynamic software FactSage 8.3, were adopted to analyze the experimental data. The results revealed that increasing the flow-rate of reduction‑carbonization regent CO (V_outer(CO)) was beneficial for the formation of Mo₂C; while when V_outer(CO) exceeded the threshold value, single-phase Mo₂C cannot be prepared. The optimal conditions for preparing ultrafine Mo₂C were given as T = 1223–1323 K, V_outer(CO) = 900 mL/min, and V_inner(Ar) = 100 mL/min; herein, V_inner(Ar) means the flow-rate of carrier gas Ar. Under these conditions, the preparation procedures of Mo₂C followed the pathways of MoO₃ → (MoO₃)_n(n = 2, 3, 4, and 5) → MoO₂ → Mo₂C. The study also discovered that the as-prepared Mo₂C kept the overall morphology as the intermediate product MoO₂ with a hexagonal-platelet structure; however, due to the removal of oxygen and the decrease of products' molar volume, the prepared Mo₂C exhibited a rougher and more porous micro-structure with a specific surface area up to 36.7 m²/g. This work may provide an important methodical guidance for the scale-preparation of ultrafine Mo₂C.

提出了CO与气态MoO3化学气相沉积法制备超细Mo2C的方法。采用XRD、FESEM、TEM、激光粒度分析、brunauer - emmet - teller法等不同技术，以及热力学软件FactSage 8.3对实验数据进行分析。结果表明：增加还原炭化剂CO （Vouter(CO)）的流量有利于Mo2C的形成；而当Vouter（CO）超过阈值时，则无法制备单相Mo2C。制备超细Mo2C的最佳工艺条件为：T = 1223 ~ 1323 K, Vouter(CO) = 900 mL/min, Vinner(Ar) = 100 mL/min；其中，Vinner（Ar）表示载气Ar的流速。在此条件下，Mo2C的制备过程为MoO3→（MoO3）n（n = 2,3,4,5）→MoO2→Mo2C。研究还发现，制备的Mo2C保持了中间产物MoO2的整体形态，具有六边形血小板结构；然而，由于氧的去除和产物摩尔体积的减小，制备的Mo2C表现出更粗糙、更多孔的微观结构，比表面积高达36.7 m2/g。该工作为超细Mo2C的规模化制备提供了重要的方法指导。

{"title":"A new method for preparing ultrafine Mo2C by the CVD reaction of CO and gaseous MoO3: Parameter optimization and its formation mechanism","authors":"Lu Wang , Bing-Han Sun , Jian-Jun Yu , Jian-Li Li","doi":"10.1016/j.ijrmhm.2025.107636","DOIUrl":"10.1016/j.ijrmhm.2025.107636","url":null,"abstract":"<div><div>In the work, the method of chemical vapor deposition reaction of CO and gaseous MoO<sub>3</sub> was proposed to prepare ultrafine Mo<sub>2</sub>C. Different technologies, such as XRD, FESEM, TEM, laser particle size analysis and Brunauer-Emmett-Teller method, as well as thermodynamic software FactSage 8.3, were adopted to analyze the experimental data. The results revealed that increasing the flow-rate of reduction‑carbonization regent CO (<em>V</em><sub>outer</sub>(CO)) was beneficial for the formation of Mo<sub>2</sub>C; while when <em>V</em><sub>outer</sub>(CO) exceeded the threshold value, single-phase Mo<sub>2</sub>C cannot be prepared. The optimal conditions for preparing ultrafine Mo<sub>2</sub>C were given as <em>T</em> = 1223–1323 K, <em>V</em><sub>outer</sub>(CO) = 900 mL/min, and <em>V</em><sub>inner</sub>(Ar) = 100 mL/min; herein, <em>V</em><sub>inner</sub>(Ar) means the flow-rate of carrier gas Ar. Under these conditions, the preparation procedures of Mo<sub>2</sub>C followed the pathways of MoO<sub>3</sub> → (MoO<sub>3</sub>)<sub><em>n</em></sub>(<em>n</em> = 2, 3, 4, and 5) → MoO<sub>2</sub> → Mo<sub>2</sub>C. The study also discovered that the as-prepared Mo<sub>2</sub>C kept the overall morphology as the intermediate product MoO<sub>2</sub> with a hexagonal-platelet structure; however, due to the removal of oxygen and the decrease of products' molar volume, the prepared Mo<sub>2</sub>C exhibited a rougher and more porous micro-structure with a specific surface area up to 36.7 m<sup>2</sup>/g. This work may provide an important methodical guidance for the scale-preparation of ultrafine Mo<sub>2</sub>C.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107636"},"PeriodicalIF":4.6,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145784611","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

High-temperature oxidation behavior and mechanism of α/β-SiAlON ceramic tool materials incorporated with SiC whiskers SiC晶须掺杂α/β-SiAlON陶瓷刀具材料的高温氧化行为及机理

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.ijrmhm.2025.107631

Duwang Liu , Zengbin Yin , Chao Liu , Dongbo Hong

SiC whisker (SiC_w)-reinforced α/β-SiAlON ceramic tool materials were fabricated via spark plasma sintering (SPS), and their high-temperature (1000–1400 °C) oxidation behavior and mechanism were studied as compared with pure α/β-SiAlON ceramics. The results showed that the addition of SiC_w significantly enhanced the oxidation resistance of SiAlON ceramics, which was attributed to the restriction of the emergence of pores and promotion of scale-like refractory phases formation by SiC_w. In addition, the oxidation resistance was decreased with the increase of the α/(α + β) ratio. Diffusion of rare earth cations (Yb³⁺, Sm³⁺) and gases (O₂, CO, and N₂) was the main rate-controlling oxidation mechanisms for α/β-SiAlON ceramic tool materials.

采用火花等离子烧结（SPS）法制备了SiC晶须增强α/β-SiAlON陶瓷刀具材料，并与纯α/β-SiAlON陶瓷进行了高温（1000 ~ 1400℃）氧化性能和机理研究。结果表明，SiCw的加入显著提高了SiAlON陶瓷的抗氧化性，这是由于SiCw抑制了孔隙的形成，促进了鳞状耐火相的形成。抗氧化性能随α/(α + β)比的增大而降低。稀土离子（Yb3+, Sm3+）和气体（O2， CO和N2）的扩散是α/β-SiAlON陶瓷刀具材料的主要速率控制氧化机制。

引用次数: 0

WO3/TiO2 composite coatings on titanium: A comprehensive review of fabrication strategies and structure/property/performance correlations in visible-light photocatalysis 二氧化钛上的WO3/TiO2复合涂层：制备策略和可见光催化结构/性能/性能相关性的综合综述

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-17 DOI: 10.1016/j.ijrmhm.2025.107630

Haniye Salimi , Arash Fattah-alhosseini , Kazem Babaei , Burak Dikici , Mosab Kaseem

Visible-light-driven photocatalysis continues to face major limitations due to insufficient light absorption and rapid charge recombination in conventional TiO₂-based systems. Integrating WO₃ with TiO₂ has emerged as a promising strategy to overcome these constraints by enhancing visible-light responsiveness and improving charge carrier dynamics. Accordingly, this review addresses the central research question: How do different fabrication routes of WO₃/TiO₂ composite coatings influence their structural features and, consequently, their photocatalytic performance under visible light? The review critically surveys recent studies on the manufacture of WO₃/TiO₂ composite coatings, with a special focus on how different preparation processes such as sol–gel, anodizing, plasma electrolytic oxidation (PEO), and hybrid routes affect their structures, optical properties, and photocatalytic activities. The formation of effective WO₃/TiO₂ heterojunctions improves carrier separation and extends light absorption, leading to significant degradation of organic pollutants or enhanced water-splitting performance. Particular attention is given to the role of morphological parameters, such as porosity, surface area, crystalline phase composition, and nanoparticle dispersion, in dictating photocatalytic activity. A comparative summary of structure–property–performance correlations is provided through examination of a broad range of experimental studies. It outlines the challenges that now exist in optimizing WO₃/TiO₂ systems in real-world environmental and energy applications. The findings presented here form the basis for rationalizing next-generation visible-light-responsive photocatalysts.

可见光驱动的光催化仍然面临着主要的限制，因为传统的tio2基系统光吸收不足和快速电荷重组。通过增强可见光响应性和改善载流子动力学，将WO3与TiO2集成成为克服这些限制的一种有希望的策略。因此，本综述解决了研究的核心问题：WO3/TiO2复合涂层的不同制备路线如何影响其结构特征，从而影响其在可见光下的光催化性能？本文综述了WO3/TiO2复合涂层的最新研究进展，重点介绍了溶胶-凝胶、阳极氧化、等离子体电解氧化（PEO）和杂化等不同制备工艺对其结构、光学性能和光催化活性的影响。有效的WO3/TiO2异质结的形成改善了载流子分离，扩大了光吸收，从而显著降解有机污染物或增强了水分解性能。特别注意形态参数的作用，如孔隙率，表面积，晶相组成，和纳米颗粒分散，在决定光催化活性。通过对广泛的实验研究的考察，提供了结构-性能-性能相关性的比较总结。它概述了在现实环境和能源应用中优化WO3/TiO2体系目前存在的挑战。本文提出的研究结果为下一代可见光响应光催化剂的合理化奠定了基础。

{"title":"WO3/TiO2 composite coatings on titanium: A comprehensive review of fabrication strategies and structure/property/performance correlations in visible-light photocatalysis","authors":"Haniye Salimi , Arash Fattah-alhosseini , Kazem Babaei , Burak Dikici , Mosab Kaseem","doi":"10.1016/j.ijrmhm.2025.107630","DOIUrl":"10.1016/j.ijrmhm.2025.107630","url":null,"abstract":"<div><div>Visible-light-driven photocatalysis continues to face major limitations due to insufficient light absorption and rapid charge recombination in conventional TiO<sub>2</sub>-based systems. Integrating WO<sub>3</sub> with TiO<sub>2</sub> has emerged as a promising strategy to overcome these constraints by enhancing visible-light responsiveness and improving charge carrier dynamics. Accordingly, this review addresses the central research question: How do different fabrication routes of WO<sub>3</sub>/TiO<sub>2</sub> composite coatings influence their structural features and, consequently, their photocatalytic performance under visible light? The review critically surveys recent studies on the manufacture of WO<sub>3</sub>/TiO<sub>2</sub> composite coatings, with a special focus on how different preparation processes such as sol–gel, anodizing, plasma electrolytic oxidation (PEO), and hybrid routes affect their structures, optical properties, and photocatalytic activities. The formation of effective WO<sub>3</sub>/TiO<sub>2</sub> heterojunctions improves carrier separation and extends light absorption, leading to significant degradation of organic pollutants or enhanced water-splitting performance. Particular attention is given to the role of morphological parameters, such as porosity, surface area, crystalline phase composition, and nanoparticle dispersion, in dictating photocatalytic activity. A comparative summary of structure–property–performance correlations is provided through examination of a broad range of experimental studies. It outlines the challenges that now exist in optimizing WO<sub>3</sub>/TiO<sub>2</sub> systems in real-world environmental and energy applications. The findings presented here form the basis for rationalizing next-generation visible-light-responsive photocatalysts.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107630"},"PeriodicalIF":4.6,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837167","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

Effects of chromium addition on the microstructure and mechanical properties of the W-Ni-Fe alloy 添加铬对W-Ni-Fe合金组织和力学性能的影响

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

International Journal of Refractory Metals & Hard Materials

Pub Date : 2025-12-15 DOI: 10.1016/j.ijrmhm.2025.107629

S. Aliakbari-Sani , H. vafaeenezhad , H. Najafi , K. Zavichi-Tork

Tungsten heavy alloys are unique composites consisting of tungsten grains in a matrix, produced only by powder metallurgy technique. This study aimed to investigate the effect of adding Cr element on the microstructure and mechanical properties of W-Ni-Fe tungsten heavy alloys, therefore two WHA and WHA-Cr alloys were designed and manufactured using the same liquid phase sintering process. The microstructural results showed that in the WHA sample, only α‑tungsten grains and γ-matrix phase were present, whereas in the WHA-Cr alloy, the chromium-rich sigma (σ) phase was also formed along with the α- and γ-phases. Furthermore, thermodynamic studies using JMatPro software showed that the potential formation of the sigma phase and decline in the liquid phase led to the retardation of sintering phenomena in the WHA-Cr alloy. The addition of chromium had undesirable effects, such as increased porosity, decreased density (17.31 g/cm³ in WHA and 16.38 g/cm³ in WHA-Cr), and increased contiguity number of W-W interfaces (from 0.21 in WHA to 0.47 in WHA-Cr). Moreover, the results showed that the hardness of the WHA was (30 HRC) lower than that of WHA-Cr (48 HRC); whereas the tensile properties of WHA (YS = 674 MPa, UTS = 942 MPa, El% = 14.5) were better than those of the WHA-Cr alloy (YS = 423 MPa, UTS = 502 MPa, El% = 3.8). These properties were attributed to the addition of chromium by two factors: (1) the formation of σ-phase, a very hard phase with an 850 HV. value, and (2) a high contiguity number, which was briefly discussed. Finally, it should be noted that although WHA-Cr alloys are undesirable for conventional applications owing to their lower overall properties, their production with least defect and high density can be suitable for some special applications with higher hardness such as wear and erosion conditions.

重钨合金是一种独特的复合材料，由钨晶粒在基体中组成，仅通过粉末冶金技术生产。为了研究添加Cr元素对W-Ni-Fe钨重合金组织和力学性能的影响，采用相同的液相烧结工艺设计并制备了WHA和WHA-Cr合金。显微组织结果表明，在WHA试样中只存在α-钨晶和γ-基体相，而在WHA- cr合金中，除了α-相和γ-相外，还形成了富铬的σ相。此外，利用JMatPro软件进行热力学研究表明，sigma相的潜在形成和液相的下降导致了WHA-Cr合金烧结现象的延迟。铬的加入会增加孔隙度，降低密度（WHA为17.31 g/cm3， WHA- cr为16.38 g/cm3），增加W-W界面的邻接数（WHA为0.21，WHA- cr为0.47）。结果表明，WHA的硬度（30 HRC）低于WHA- cr的硬度（48 HRC）；而WHA合金（YS = 674 MPa, UTS = 942 MPa, El% = 14.5）的拉伸性能优于WHA- cr合金（YS = 423 MPa, UTS = 502 MPa, El% = 3.8）。这些性能是由于铬的加入造成的：(1)形成了一种850 HV的极硬相σ-相。值，(2)为高邻接数，对此进行了简要讨论。最后，值得注意的是，尽管由于其整体性能较低，WHA-Cr合金不适合常规应用，但其生产的缺陷最少，密度高，可以适用于一些具有较高硬度的特殊应用，如磨损和侵蚀条件。

{"title":"Effects of chromium addition on the microstructure and mechanical properties of the W-Ni-Fe alloy","authors":"S. Aliakbari-Sani , H. vafaeenezhad , H. Najafi , K. Zavichi-Tork","doi":"10.1016/j.ijrmhm.2025.107629","DOIUrl":"10.1016/j.ijrmhm.2025.107629","url":null,"abstract":"<div><div>Tungsten heavy alloys are unique composites consisting of tungsten grains in a matrix, produced only by powder metallurgy technique. This study aimed to investigate the effect of adding Cr element on the microstructure and mechanical properties of W-Ni-Fe tungsten heavy alloys, therefore two WHA and WHA-Cr alloys were designed and manufactured using the same liquid phase sintering process. The microstructural results showed that in the WHA sample, only α‑tungsten grains and γ-matrix phase were present, whereas in the WHA-Cr alloy, the chromium-rich sigma (σ) phase was also formed along with the α- and γ-phases. Furthermore, thermodynamic studies using JMatPro software showed that the potential formation of the sigma phase and decline in the liquid phase led to the retardation of sintering phenomena in the WHA-Cr alloy. The addition of chromium had undesirable effects, such as increased porosity, decreased density (17.31 g/cm<sup>3</sup> in WHA and 16.38 g/cm<sup>3</sup> in WHA-Cr), and increased contiguity number of W-W interfaces (from 0.21 in WHA to 0.47 in WHA-Cr). Moreover, the results showed that the hardness of the WHA was (30 HRC) lower than that of WHA-Cr (48 HRC); whereas the tensile properties of WHA (YS = 674 MPa, UTS = 942 MPa, El% = 14.5) were better than those of the WHA-Cr alloy (YS = 423 MPa, UTS = 502 MPa, El% = 3.8). These properties were attributed to the addition of chromium by two factors: (1) the formation of σ-phase, a very hard phase with an 850 HV. value, and (2) a high contiguity number, which was briefly discussed. Finally, it should be noted that although WHA-Cr alloys are undesirable for conventional applications owing to their lower overall properties, their production with least defect and high density can be suitable for some special applications with higher hardness such as wear and erosion conditions.</div></div>","PeriodicalId":14216,"journal":{"name":"International Journal of Refractory Metals & Hard Materials","volume":"136 ","pages":"Article 107629"},"PeriodicalIF":4.6,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837166","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