ADVANCED POWDER TECHNOLOGY
·
2022
·
IF 4.969
He Zhang,Jun-Ru Liu,Zhi-Bo Li,Xiao-Chun Deng,Guo-Hua Zhang,Kuo-Chih Chou
In this study, high-performance fine-grained W-Cu sintered blocks with the addition of dispersed Al 2 O 3 particles were successfully produced by low temperature liquid-phase sintering, using the raw material of ultrafine W-Cu alloy powder. The ultrafine W-Cu alloy powder was obtained by a two-step reduction process composed of stages of carbothermal reaction and hydrogen deep deoxidation. The fine Al 2 O 3 grains with uniform distribution in W-Cu alloy were introduced by spray method, leading to the decrease of W grain size and W-W connectivity. The relative densities of all sintered blocks were>97%, and a higher degree of densification ensures that the alloy has excellent comprehensive properties. With the increase of Al 2 O 3 content, W grain size and W-W connectivity of sintered W-Cu samples decrease from 664 nm to 472 nm and 0.2 to 0.14, respectively. The W-Cu alloy with the ultimate tensile strength of 415 MPa and the highest elongation of 7.22% was obtained when the addition amount of Al 2 O 3 was 0.5 wt%. At the same time, it also possessed the maximum bending strength of 1028 MPa and microhardness of 312 HV, respectively. In addition, due to the good network structure of Cu and uniform three-phase distribution, the sintered samples had excellent conductivity and compressive strength.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Junjie Xu,Wei Sun,Xiang Xiong,Hongbo Zhang
Compared with the traditional C/C composites modified by ultra-high-temperature ceramics (C/C-UHTCs), those modified by metal/medium-entropy ceramics have excellent mechanical properties, thermophysical properties, and long-term ablation resistance. These composites have great potential towards improving the high-temperature resistance and service life of thermal protection systems for spacecraft. In this study, a new type of (Hf 0.5 Zr 0.3 Ti 0.2 )C–W–Cu cermet-modified C/C composites (C/C-(Hf 0.5 Zr 0.3 Ti 0.2 )C–W–Cu) was prepared at 1500 °C. Compared with C/C-UHTCs, the bending strength and fracture toughness of C/C-(Hf 0.5 Zr 0.3 Ti 0.2 )C–W–Cu increased by 70 % and 110 % to 364.25 MPa and 14.64 MPa m 1/2 , respectively. Due to the high thermal conductivity of Cu and W, the thermal conductivity of this new composite was 106 % higher than that of C/C-(Hf 0.5 Zr 0.3 Ti 0.2 )C (44.26 versus 21.53 W/m·K). Under a high heat flow of 4.18 MW/m 2 , this material exhibited very low mass and linear ablation rates (−0.163 mg/s and −0.193 μm/s, respectively). Active and passive protection occur during ablation due to the evaporative cooling of Cu, CuO, and WO 3 as well as a dense outer oxide layer that inhibits oxygen diffusion. The internal oxide layer forms a Hf-Zr-Ti-C-O framework mingled with Ti-rich Ti-Hf-Zr-C-O and an unoxidised W–Cu structure, effectively reducing the osmotic oxygen content. This work provides a new direction for developing thermal protection materials capable of long-term service in ultra-high-temperature environments.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Junjie Xu,Wei Sun,Xiang Xiong,Hongbo Zhang,Lingkun Yang
Spacecraft thermal protection materials need to survive long-term exposure to oxygen-containing environments at 2400 °C. In this study, a high-density and low-porosity metal-ceramic-modified composite was prepared at a low temperature (1500 °C) in the presence of W and Cu using combined slurry brushing and reactive melt infiltration methods. An investigation of the composite formation mechanism and the effects of W and Cu indicated that W and ZrB 2 were formed via dissolution-precipitation and the external diffusion of C and B, respectively. The low reaction temperature and the metallic phases significantly improved the mechanical properties, thermophysical properties, and long-term ablation behaviours of C/C–ZrC–ZrB 2 –W–Cu. Compared to traditional C/C–ZrC, the flexural strength and fracture toughness of the composite increased by 71.56 % and 90.05 % to 345.95 MPa and 14.52 MPa m 1/2 , respectively, and the thermal conductivity increased by 174.93 % to 59.11 W/m·K. In addition, W and Cu effectively lowered the surface temperature by nearly 250 °C during 300 s ablation, and the mass and line ablation rates decreased to −0.272 mg/s and −0.247 μm/s, respectively.
研究领域:
材料科学
·
航天工程
✓ 已验证
产品关联
DOI
高影响因子
POWDER METALLURGY
·
2020
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IF 1.793
Dongxue Liu,Qiqi Zhang,Longchao Zhuo,Yiheng Zhang,Yanlin Wang,Jintao Xu
In this paper, a combined processing method of mechanical alloying and infiltration was used to prepare the WCu-x wt-%SiC (x = 0.5, 1, 2, 3) composites. The microstructure, density, electrical conductivity and compressive behaviour of the composites were studied comparatively. First a decreasing and then an increasing particle growth trend was obtained, indicating that a small content of SiC below 1 wt-% was beneficial for particle refinement. Besides this, with the increase of the SiC content, both the density and electrical conductivity decreased gradually. Consistent with the particle–particle contiguity of the highest value of 0.404, the WCu-1 wt-%SiC composite showed the best compressive properties. Further electron backscattering diffraction results revealed that the ultrafine-grained SiC particles, which are distributed homogeneously in the composite with lower Schmid factor values would perturb the dislocation motion to make proliferation of more dislocations, exhibiting unordinary strain-hardening during deformation.
研究领域:
材料科学
·
金属学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHARACTERIZATION
·
2025
·
IF 5.5
Dang Xu,Pengqi Chen,Kaichao Fu,Changcheng Sang,Ruizhi Chen,Tao Hong,Jigui Cheng,Kai Xu
The inherent metallurgical incompatibility between dissimilar metals such as tungsten (W) and copper (Cu) engenders weak chemical bonding, substantially constraining the attainment of high strength. This constitutes a critical limitation for nuclear fusion applications demanding robust interfacial integrity. To address these limitations, this study introduces a dual interface reinforcement strategy employing a CrCoNi medium entropy alloy (MEA) interlayer and achieving diffusion bonding of oxide diffusion-strengthened tungsten (ODS-W) and Cu through spark plasma sintering (SPS) technology. At the optimized bonding temperature of 1000 °C, the joint achieves a maximum tensile strength of 256.7 ± 8.2 MPa, corresponding to a 171 % enhancement over direct bonding (DB) joint (94.6 ± 5.1 MPa), accompanied by a fracture mode transition from brittle to ductile failure. Multi-scaled microstructure and interface element diffusion behavior analyses reveal that reactive diffusion at the W/MEA interface facilitates the formation of a solution-strengthened matrix associated with an amorphous diffusion layer. Whereas mutual diffusion at the Cu/MEA interface induces multiple phase structures, resulting concurrently in solid solution strengthening and precipitation strengthening, thereby reinforcing the interface bonding. This dual interface reinforcement methodology establishes an effective design strategy for enhancing mechanical properties in immiscible metal systems.
研究领域:
材料科学
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冶金学
·
核工程
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机械工程
·
连接技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2022
·
IF 10.319
Zhi Zhao,Fawei Tang,Chao Hou,Xintao Huang,Xiaoyan Song
Characterizing immiscible metallic composites with electron microscopy and X-ray spectroscopy is the classic way of obtaining their structural and physical details. Nevertheless, such a combination lacks ability to tell the interfacial interactions at grain boundaries. Here we demonstrate a novel strategy to uncover the mystery of interfacial interactions in such systems by spectroscopic microscopy. The morphological and spectral data of samples were simultaneously recorded and analyzed, which reveals critical information regarding interfacial electronic modes. Taking W-Cu as a model, we experimentally quantified its connectivity and unambiguously identified conditional bonding between W and Cu. Further, we chemically reconstructed the specific W-Cu boundary that possessed the strongest interactions and investigated its atomic structure. The mechanism of W-Cu bonding was proposed and verified by first-principle calculations. The above methodology holds great promise to serve as a universal approach in achieving in-depth understanding of immiscible composites.
研究领域:
材料科学
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冶金学
·
显微镜技术
·
光谱学
✓ 已验证
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
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2019
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IF 3.327
Jun-Kai Liu,Kai-Fei Wang,Kuo-Chih Chou,Guo-Hua Zhang
Ultrafine W-Cu composite powders with various copper (Cu) contents (5, 20 and 40 wt.%) have been fabricated by a method consisting of a carbothermic pre-reduction step and a subsequent hydrogen reduction step. After roasting the mixture of ammonium tungstate ((NH 4 ) 10 [H 2 W 12 O 42 ]· x H 2 O) and copper nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O), the mixture of CuWO 4 and CuO (or WO 3 ) was obtained. Subsequently, this mixture was pre-reduced by insufficient carbon black to generate the products containing W, Cu and a small amount of WO 2 which was further reduced to W in the following hydrogen reduction process. Thus, the ultrafine W-Cu composite powders were successfully produced. After sintering the green compacts made of these powders at 1100 ℃, 1150 ℃, 1200 ℃ and 1250 ℃, respectively, the microstructure, relative densities, electric conductivity and thermal conductivity of the sintered alloys were measured. The experimental results indicated that the higher the sintering temperature is, the better the performance of alloys will be.
研究领域:
材料科学
·
冶金工程
✓ 已验证
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2011
·
IF 2.141
Qiang Chen,Dun-qiang Tan,Rui Liu,Wen-xian Li
Electrodepositing Al coatings on W 90 Cu 10 foils in AlCl 3 + LiAlH 4 Tetrahydrofuran–benzene electrolyte was reported in this work. Effects of variations in molar ratios of AlCl 3 /LiAlH 4 , current density and plating time on surface morphology and crystal orientations were studied, and the optimal values of three parameters were preliminarily gained. Results showed that Al coatings displayed dense and cone-shaped micro-crystallites, and the particle size of coatings increased obviously with increasing current density or decreasing the proportion of AlCl 3 . It was indicated that all of the electrodeposits exhibited a strong preferred (111), (220) crystal orientation, and the (220) crystal orientation became strong along with electroplating time and current density, but weak with the proportion of AlCl 3 in baths. On the contrary, the changes of the (111) orientation exhibited an opposite trend.
研究领域:
材料科学
·
电化学
·
表面工程
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2023
·
IF 6.4
He Zhang,Guo-Hua Zhang
In this paper, using the ultrafine W-27.5 wt%Cu-2wt.%Mo-1.75 wt%Ni-0.75 wt%Fe-(0–1)wt.%CeO 2 alloy powders as raw materials, W–Cu–Mo–Ni–Fe–CeO 2 alloys with excellent performances were prepared by low temperature sintering . Two-step reduction method consisting of carbothermic pre-reduction and hydrogen deep deoxidation was used to produce ultrafine W–Cu–Mo–Ni–Fe–CeO 2 alloy powders with uniform distributed composition. All sintered blocks obtained relatively high densification degree (97.1 %∼99.2 %) to ensure the excellent comprehensive properties. Moreover, the existences of γ-(Cu, Ni, Fe) and W–Mo solid solutions ensured the alloy possessed a high mechanical strength . More importantly, the introduction of CeO 2 inhibited the growth of W–Mo grains. With increasing CeO 2 content from 0 wt% to 1 wt%, the W–Mo grain size decreased from 1.76 μm to 1.44 μm. Especially, alloy sample with the highest tensile and compressive strengths was obtained by adding 0.5 wt% CeO 2 , which were 602 MPa and 3187 MPa, respectively. Furthermore, owing to finer W–Mo grain size, this sample also possessed the maximum micro-hardness and bending strength of 482 H V and 1685 MPa, respectively. Nevertheless, the existences of Ni, Fe and CeO 2 also destroyed the electrical conductivities of the samples to some extent. Specifically, with increasing CeO 2 content from 0 wt% to 1 wt%, the electrical conductivity of the sample decreases from 32.56 %IACS to 30.16 %IACS.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2026
·
IF 5.1
Yufeng Liu,Xiaofan Yang,Jinghua Hu,Junhao Liu,Peiwen Wu,Huifang Cheng,Huaming Li,Jixing Liu,Wenshuai Zhu
The hydroisomerization of isobutane is of considerable practical significance for the development of low-carbon and high-efficiency ethylene production technologies. However, conventional noble metal-solid superacid catalysts used for this reaction suffer from drawbacks including high cost and catalyst deactivation caused by the loss of halogen species and other active components. Herein, a series of highly dispersed W-Cu/Beta catalysts were designed and prepared via a facile ion-exchange method, and their catalytic performances toward isobutane hydroisomerization were systematically investigated. The results show that the introduction of WO x species effectively suppresses strong Brønsted acid sites of the Beta zeolite and modifies the Brønsted/Lewis acid balance of W-Cu/Beta catalysts. Although both Brønsted and Lewis acid site concentrations decrease with increasing W loading, Brønsted acidity is reduced to a greater extent, resulting in a lower Brønsted/Lewis acid site ratio. This acidity regulation is associated with suppression of undesired cracking reactions and improved selectivity toward n-butane. Under reaction conditions of 2 MPa, 380°C, and a weight hourly space velocity of 2.0 h ‒1 , the 5%W-Cu/Beta catalyst exhibits the best catalytic performance with isobutane conversion of 62.3% and n-butane yield of 32.4%. This enhanced catalytic behavior is attributed to optimized acidity and an appropriate distribution of catalytic active sites. Kinetic analyses indicate that WO x introduction alters the apparent kinetic behavior of the catalysts and is accompanied by an increase in apparent activation energy. The improved catalytic selectivity is correlated with changes in acidity distribution and suppression of cracking pathways rather than direct evidence of carbocation stabilization.
✓ 已验证
产品关联
DOI
高影响因子
Engineering
·
2024
·
IF 10.1
Qixiang Duan,Chao Hou,Tielong Han,Yurong Li,Haibin Wang,Xiaoyan Song,Zuoren Nie
Immiscible bimetal systems, of which tungsten–copper (W–Cu) is a typical representative, have crucial applications in fields requiring both mechanical and physical properties. Nevertheless, it is a major challenge to determine how to give full play to the advantages of the two phases of the bimetal and achieve outstanding comprehensive properties. In this study, an ultrafine-grained W–Cu bimetal with spatially connected Cu and specific W islands was fabricated through a designed powder-mixing process and subsequent rapid low-temperature sintering. The prepared bimetal concurrently has a high yield strength, large plastic strain, and high electrical conductivity. The stress distribution and strain response of individual phases in different types of W–Cu bimetals under loading were quantified by means of a simulation. The high yield strength of the reported bimetal results from the microstructure refinement and high contiguity of the grains in the W islands, which enhance the contribution of W to the total plastic deformation of the bimetal. The high electrical conductivity is attributed to the increased mean free path of the Cu and the reduced proportion of phase boundaries due to the specific phase combination of W islands and Cu. This work provides new insight into modulating phase configuration in immiscible metallic composites to achieve high-level multi-objective properties.
研究领域:
材料科学
·
金属学
✓ 已验证
DOI
高影响因子
Materials Today Chemistry
·
2022
·
IF 7.613
Mingzhen Huang,Siyuan Hu,Dongren Cai,Guowu Zhan
It is a significant method to prepare highly dispersed polymetallic oxides using in-situ doping metal organic frameworks as precursors. Herein, a series of straw-like W/Cu/Ce trimetallic oxides were prepared by using phosphotungstic ionic liquid@Ce-based metal organic framework adsorbing with copper acetylacetonate as precursors. The effect of W content on catalytic activity of W/Cu/Ce trimetallic oxides for carbon monoxide (CO) oxidation was well-investigated. Comprehensive characterization methods and density functional theory calculations were adopted to reveal the property changes of Cu/CeO 2 catalyst by the addition of W. The results demonstrated that W, Cu, and Ce are highly dispersed in the prepared W/Cu/Ce trimetallic oxides, and adding proper amount of W can improve the activity of the catalyst. H 2 temperature-program reduction profiles, X-ray photoelectron spectroscopy, in-situ diffuse reflectance infrared Fourier transform spectroscopy , and density functional theory calculations clearly revealed that after the addition of W, the strength of Ce-O bond is weakened, the oxygen vacancy is increased, and the adsorption of CO is enhanced, respectively, which are vital reasons for its high catalytic activity. In addition, the CO oxidation reaction pathway over prepared W/Cu/Ce trimetallic oxides based on the Mars-van Krevelen mechanism was studied, and the results exhibited that CO can wrest the lattice oxygen of W/Cu/Ce trimetallic oxides to form CO 2 , which is also proved to be the rate-determining step in reaction process.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）