MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
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2025
·
IF 7
Yu He,Shengwei Xin,Baoru Sun,Xuecheng Cai,Yapeng Lin,Lingwei Kong,Xun Shen,Congcong Du,Xiaoyuan Yuan,Kangkang Wen,Tongde Shen
Metals are often soft while ceramics are often hard. To make metals as hard as ceramics has been long-awaited in metals and ceramics communities. In this study, bulk nanocrystalline (NC) tungsten-1 wt% yttrium-0.7 wt% titanium (WYT) was fabricated via mechanical alloying followed by high-temperature/high-pressure sintering. The high pressure directly inhibits grain growth by suppressing atomic diffusion and indirectly inhibits grain growth by lowering sintering temperature, enabling the synthesis of dense NC WYT bulks with an average grain size of ∼ 9.0 nm. The high temperature causes annealing- and segregation-induced structural relaxation of grain boundaries (GBs) in sintered bulk NC WYT, resulting in GBs with a small excess volume of only ∼ 0.005 nm, one fifth that of bulk NC tungsten. The small grain size and the relaxed GBs in the bulk NC WYT make it hard for GBs to emit dislocations, resulting in extremely high hardness of 23.2 ± 0.3 GPa, yield strength of 9.4 ± 0.3 GPa, and ultimate compressive strength of 13.1 ± 1.1 GPa. The hardness of metallic bulk NC WYT is comparable to that of ceramic tungsten carbide (WC) whereas the wear rate of bulk NC WYT is even lower than that of WC. The structure-relaxed GBs lower the thermodynamic driving force for grain growth and result in an extremely high thermal stability - no grain growth occurs in bulk NC WYT annealed at a high temperature of 1500 °C, which is above the recrystallization temperature of tungsten. The present strategy - multifunctional treatments of NC alloy powders by high-temperature/high-pressure - provides a huge potential to manufacture dense bulk NC materials with exceptional mechanical property and thermal stability for practical applications.
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JOURNAL OF ELECTRONIC MATERIALS
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2017
·Vol. 47
·期 6
·3248-3253
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IF 1.579
Chen Jun-Liang,Liu Chengyan,Miao Lei,Gao Jie,Zheng Yan-yan,Wang Xiaoyang,Lu Jiacai,Shu Mingzheng
With excellent high-temperature stability (up to 1000 K) and favorable electrical properties for thermoelectric application, TiNiSn-based half-Heusler (HH) alloys are expected to be promising thermoelectric materials for the recovery of waste heat in the temperature ranging from 700 K to 900 K. However, their thermal conductivity is always relatively high (5–10 W/mK), making it difficult to further enhance their thermoelectric figure-of-merit ( ZT ). In the past decade, introducing nano-scale secondary phases into the HH alloy matrix has been proven to be feasible for optimizing the thermoelectric performance of TiNiSn. In this study, a series of TiNiSn-based alloys have been successfully synthesized by a simple solid-state reaction. The content and composition of the heterogeneous phase (TiNi 2 Sn and Sn) is accurately regulated and, as a result, the thermal conductivity successfully reduced from 4.9 W m −1 K −1 to 3.0 Wm −1 K −1 (750 K) due to multi-scale phonon scattering. Consequently, a ZT value of 0.49 is achieved at 750 K in our TiNiSn-based thermoelectric materials. Furthermore, the thermal stability of TiNiSn alloys is enhanced through reducing the Sn substance phase.
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Journal of Advanced Ceramics
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2017
·Vol. 7
·期 1
·41-49
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IF 1.198
Peng Le,Zhang Kuibao,He Zongsheng,Yin Dan,Xue Jiali,Xu Chen,Zhang Haibin
In this research, Zr-doped Gd 2 Ti 2 O 7 pyrochlores, with the composition of Gd 2 (Ti 1- x Zr
x
) 2 O 7 , were firstly synthesized by self-propagating high-temperature synthesis plus quick pressing (SHS/QP) using CuO as the oxidant and Ti as the reductant. To improve the radiation resistance of titanate–pyrochlore, up to 35 at% Zr was incorporated to substitute the Ti site of Gd 2 Ti 2 O 7 pyrochlore (Gd 2 (Ti 0.75 Zr 0.35 ) 2 O 7 ). XRD and SEM microstructural characterizations showed the formation of a composite ceramic with the major pyrochlore phase and the minor Cu phase. The generated temperature of samples decreased from 1702 to 1011°C with increasing Zr content. The effects of sintering temperature and pressure time on phase composition and microstructure were systematically studied. Besides, the influence of thermal transmission on the whole combustion process was also explored. The pyrochlore-based waste form possessed high bulk density of 6.25 g/cm 3 and Vickers hardness of 10.81 GPa. The MCC-1 leaching test showed the normalized elemental leaching rates (42 d) of Cu, Gd, and Zr are 1.27×10 -2 , 1.33×10 -3 , and 8.44×10 -7 g·m -2 ·d -1 , respectively.
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Advances in Applied Ceramics
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2018
·
IF 1.092
Kuibao Zhang,Dan Yin,Xirui Lu,Haibin Zhang
In this study, the zirconolite-rich composite was rapidly synthesised from self-propagating high-temperature synthesis plus quick pressing using MoO3 as the oxidant and Ti as the reductant. As a surrogate of trivalent actinides, Nd was introduced to substitute the Ca site of zirconolite and Al was employed as the charge compensator to replace the Ti site (nominally Ca1−xNdxZrTi2−xAlxO7). The phase composition and Nd occupancy were analysed after Nd2O3 addition. Nd-bearing zirconolite was produced as the major ceramic phase. Nd mostly substitutes the Ca sites of zirconolite, which results in waste loading higher than 8.6 wt-% Nd. The aqueous durability of Nd–Al codoped sample (with 15 at.-% Nd substitutes the Ca site of zirconolite) was evaluated at 90°C as well. The 42 days normalised leaching rates of Mo, Ca and Nd were measured to be 3.70, 1.90 × 10−2 and 3.46 × 10−4 g m−2 d−1.
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Inorganics
·
2025
·Vol. 13
·期 3
·74
·
IF 3
Yan Chu,Shiwei Fang,Yingjue Chen,Xiaoqi Zhang,Jie Zheng,Zhenglong Li,Wubin Du,Wengang Cui,Jian Miao,Yaxiong Yang,Yongfeng Liu,Mingxia Gao,Hongge Pan
LiAlH4, characterized by high hydrogen capacity and metastable properties, is regarded as a promising hydrogen source under mild conditions. However, its reversible regeneration from dehydrogenated production is hindered thermodynamically and kinetically. Herein, we demonstrate an active Li–Al–Ti nanocrystalline alloy prepared by melt spinning and cryomilling to enable directly synthesizing nano-LiAlH4. Due to the non-equilibrium preparation methods, the grain/particle size of the alloy was reduced, stress defects were introduced, and the dispersion of the Ti catalyst was promoted. The refined Li–Al–Ti nanocrystalline alloy with abundant defects and uniform catalytic sites demonstrated a high reactivity of the particle surface, thereby enhancing hydrogen absorption and desorption kinetics. Nano-LiAlH4was directly obtained by ball milling a 5% Ti containing Li–Al–Ti nanocrystalline alloy with a grain size of 17.4 nm and Al3Ti catalytic phase distributed under 20 bar hydrogen pressure for 16 h. The obtained LiAlH4exhibited room temperature dehydrogenation performance and good reversibility. This finding provides a potential strategy for the non-solvent synthesis and direct hydrogenation of metastable LiAlH4hydrogen storage materials.
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CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jiale Zhang,Jianjun Chen,Jinyu Guo,Hao Chen,Longbo Xue,Chenyu Li
In this study, silicon nitride (Si 3 N 4 ) powders with high α-phase content and rod-like crystal morphologies were synthesized via self-propagating high-temperature synthesis (SHS) in a low-pressure nitrogen atmosphere (0.2 MPa), using silicon and Si 3 N 4 powders as reactants, with magnesium powder serving as an igniter. The influence of different ratios of silicon to silicon nitride on the phase composition, crystal morphology, and sintering activity of the synthesized Si 3 N 4 powders was systematically investigated. The results demonstrated that controlling the silicon-to-silicon nitride ratio under low-pressure conditions significantly affects the formation of α-phase Si 3 N 4 and the resulting microstructure of the powders. A low-pressure nitrogen atmosphere was adopted based on kinetic and thermodynamic analyses, providing a feasible environment for SHS. Notably, in situ formation of magnesium nitride (MgSiN 2 ) during the reaction not only acted as an effective sintering aid but also improved the thermal conductivity of the resulting Si 3 N 4 ceramic. The powder produced from a reaction using a raw material composition of 65% Si minimizes both silicon infiltration and melting to the greatest extent, and consequently, the sintered silicon nitride ceramics exhibit the highest thermal conductivity. The low-pressure environment effectively moderated the reaction rate and temperature, promoting the formation of fine α-phase Si 3 N 4 particles with rod-like morphologies. This innovative method offers a cost-effective and environmentally friendly approach for producing high-quality Si 3 N 4 powders with high sintering activity.
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JOURNAL OF POWER SOURCES
·
2017
·
IF 6.395
Yapeng Tian,Chenhui Yang,Wenxiu Que,Yucheng He,Xiaobin Liu,Yangyang Luo,Xingtian Yin,Ling Bing Kong
Supercapacitor , as an important energy storage device, is a critical component for next generation electric power system , due to its high power density and long cycle life. In this study, a novel electrode material with quasi-core-shell structure, consisting of negatively charged few layer Ti 3 C 2 nanosheets (FL-Ti 3 C 2 ) and positively charged polyethyleneimine as building blocks, has been prepared by using an electrostatic layer-by-layer self-assembly method, with highly conductive Ni foam to be used as the skeleton. The unique quasi-core-shell structured ultrathin Ti 3 C 2 nanosheets provide an excellent electron channel , ion transport channel and large effective contact area, thus leading to a great improvement in electrochemical performance of the material. The specific capacitance of the binder-free FL-Ti 3 C 2 @Ni foam electrodes reaches 370 F g −1 at the scan rate of 2 mV s −1 and a specific capacitance of 117 F g −1 is obtained even at the scan rate of 1000 mV s −1 in the electrolyte of Li 2 SO 4 , indicating a high rate performance. In addition, this electrode shows a long-term cyclic stability with a loss of only 13.7% after 10,000 circles. Furthermore, quantitative analysis has been conducted to ensure the relationship between the capacitive contribution and the rate performance of the as-fabricated electrode.
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NEW JOURNAL OF CHEMISTRY
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2025
·
IF 2.5
Si Guo,Chao Deng,Gang Shi,Dawei Wang,Likui Wang
MXenes are emerging as highly promising materials for pseudocapacitive applications, offering exceptionally high specific capacitance. To date, over 30 distinct MXene compositions and nearly 20 solid solutions have been synthesized in the lab. However, research predominantly centers on Ti3C2Tx and a handful of other single-metal MXenes, with scant attention paid to solid-solution MXenes. Herein, a series of solid solution MAX phases (Nb1−yTiy)4AlC3 and corresponding (Nb1−yTiy)4C3Tx MXenes have been synthesized. The maximum proportion of Ti that can be incorporated into the M site has been examined. We found that the rate performance of MXenes improves with increasing Ti content. Especially, (Nb0.7Ti0.3)4C3Tx and (Nb0.6Ti0.4)4C3Tx retain 62.92% and 68.38% of their capacitances, when the scan rate is increased from 5 mV s−1 to 1000 mV s−1, respectively, compared to Nb4C3Tx's 13.88% retention. (Nb0.7Ti0.3)4C3Tx shows a specific capacitance of 311.06 F g−1 under a current density of 1 A g−1 and good cycling stability. This research demonstrates that the electrochemical characteristics of (Nb1−yTiy)4C3Tx solid solution MXenes can be manipulated by adjusting the ratio of transition metals.
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Nature Communications
·
2025
·Vol. 16
·期 1
·1-13
·
IF 15.7
Liu Shaojia,Deng Jingjing,Zhao Hewei,Wang Tianbai,Lu Junfeng,Ding Baosen,Guo Tianqi,Ritchie Robert O.,Guo Lin
Stiffness-damping balance, high specific mechanical performance, and corrosion resistance are demanded for metals. Here, we developed an enamel-inspired ceramic (EIC) coating strategy involving hydrothermal growth of a tooth enamel-like ZrO₂ nanorods on Zr foil and amorphous ZrO₂ intergranular phase formation via controlled hydrolysis. The EIC coated Zr foil (Zr-EIC) achieved a high viscoelastic figure of merit (4.6 GPa); as well as excellent specific stiffness and hardness owing to the lightweight of ceramics, surpassing the values of Zr and previously reported Zr-based alloys or Zr-based composites. This was due to the vertically oriented stiff nanorods and unique energy dissipation derived from deformation at the crystalline/amorphous interfaces. It demonstrated exceptional NaCl corrosion resistance. This approach showed universality across Ti, Zn, and Cu substrates, enhancing both mechanical properties and corrosion resistance. By constructing an enamel-like hierarchical structure on the metal surface, the strategy overcomes traditional metal limitations without causing an increase in density.
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INTERMETALLICS
·
2025
·
IF 4.8
Liangcai Du,Xiaoqing Liu,Qianqian Kong,Lichao Gong,Zhenhua Yao
Understanding the intricate phase transformations and their impact on the mechanical properties holds paramount importance in developing high entropy alloys (HEAs) with ideal properties, yet it remains challenging and underexplored. In this study, a series of novel CrFeMnNi (2-x) Ti x (x = 0, 0.5, 1, and 1.5 at.%) HEAs were meticulously designed based on the established Valence Electron Concentration (VEC) rule, with the VEC values systematically varied as the atomic composition (Ni, Ti) changed. The microstructure, phase transformation behavior, mechanical properties, and strengthening mechanisms were systematically investigated. We found that the HEA powders exhibited phase behavior consistent with the VEC rules. The spark plasma sintered (SPSed) HEA bulk samples exhibited a phase transformation attributed to the precipitation of Cr and Mn within the matrix, resulting in the formation of the σ phase. Quantitative calculation of the strengthening mechanisms revealed that grain boundary strengthening and precipitation strengthening were the primary contributors to the high strength of the HEA bulk samples. These findings not only advance the utilization of the VEC rules in HEA material design but also contribute to the understanding of the phase behavior and mechanical properties of HEAs, facilitating the design of high performance HEAs.
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EUROPEAN POLYMER JOURNAL
·
2025
·
IF 6.3
Yifei Ding,Wenxun Sun,Hongwei Gao,Ruiyu Zhang,Xiaobin Yang,Yongping Bai,Shuai Sun
High-transmittance polyester films are critical for advanced display technologies, yet the relationship between catalyst design and optical performance remains poorly understood. This work investigates seven metal-based catalysts and develops an economical and efficient composite catalyst accordingly. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of these catalysts are calculated using density functional theory (DFT) method. Results demonstrate that catalysts with lower LUMO energy levels can significantly promote nucleophilic attack during polycondensation, consequently exhibiting superior catalytic efficiency. Subsequently, we prepare a composite catalyst composed of cobalt(II) acetate tetrahydrate and germanium(IV) oxide. By employing the composite catalyst, the synthesized PET films achieved promising transmittance of 91.43 % and luminosity of 92.82 %. This study provides a DFT-driven strategy for designing optical polyesters, offering a scalable approach for advanced display applications.
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LANGMUIR
·
2025
·
IF 3.9
Xi Zhang,Xixun Shen,Qian Chen,Jianping Tao,Wang Tang,Qunjie Xu
Surface icing poses a great challenge to the safe operation and energy output of wind turbines in low-temperature freezing rain environments. To address the problem of ice cover, we designed a durable superhydrophobic MWCNTs@[F-SiO2/TiN] composite anti-icing coating with a double-layer structure, where carbon nanotubes serve as the bottom layer and titanium nitride and fluorinated silica particles serve as the top layer. The introduction of TiN nanoparticles enhances the solidification rheological uniformity of the dispersion system of silica, resulting in the formation of a dense surface with a uniform micro/nanostructure. Such a micro/nanostructure not only endows the coating with excellent superhydrophobicity, with a large contact angle of about 171° and a small rolling angle of less than 1°, but also significant anti-icing performance. The freezing time of the water droplet on this composite coating was significantly delayed to 730 s at −20 °C in the static anti-icing experiment, which is about twice that of the pure silica coating. The simulated dynamic freezing rain experiments also show that this superhydrophobic coating can effectively prevent ice formation on the surfaces of fan blades. This composite coating also exhibits excellent electrical and photothermal effects, derived from its special double-layer structure and the ability of the titanium nitride external filler to reduce heat dissipation. Under the combined action of photothermal and electrothermal effects, this composite coating demonstrates excellent deicing ability, achieving rapid deicing within 206 s, about 25.2% improvement in deicing efficiency compared to coatings without TiN. In addition, this composite coating also exhibits superior structural and performance stability, even after thermal cycling, sand and water impact, and prolonged immersion in acid/alkali corrosion. The current results suggest that the designed superhydrophobic coating with a double-layer structure is a very promising candidate for practical anti-icing and deicing applications.
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