Materials Today Physics
·
2024
·
IF 10
Yuping Duan,Meiqi Li,Yuan Guo,Ning Zhu,Huifang Pang,Chenxu Dou
High-entropy alloys, as a novel type of absorber, exhibit exceptional electromagnetic modulation capabilities and significant potential for electromagnetic wave absorption. In this work, the FeCoNiCrMn high-entropy alloy absorbent prepared through a mechanical alloying process demonstrates a dual-phase solid solution structure comprising face-centered cubic (FCC) and body-centered cubic (BCC) phases. By varying the manganese (Mn) content in the system, it is possible to enhance the degree of crystallinity, maintain the integrity of the crystal structure, and effectively control the relative proportion of the BCC phase within the overall phase composition. This adjustment improves the brittleness of the sheet-like particles, reduces particle size, and significantly lowers the permittivity. When the molar ratio of Mn is 0.6, the sample exhibits improved impedance matching due to the optimal permittivity and permeability. Notably, the impedance matching and attenuation constant can also be balanced. At 6.42 GHz, the FeCoNiCr 0.4 Mn 0.6 alloy powder achieves the maximum reflection loss of −48.49 dB at a matching layer thickness of 3 mm. When the matching thickness is reduced to 2 mm, it can effectively cover a frequency range of 8.7–14.1 GHz (effective absorption bandwidth of 5.4 GHz), along with a wide absorption bandwidth and high absorption efficiency.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2025
·
IF 4.7
Changjin Xu,Yinglei Liu,Huiqing Guo,Chun Du,Gaowu Qin,Song Li
The ability to finely tune the nuclearity of active metal sites is critical for designing highly selective catalysts, especially for hydrogenation processes. In this work, we developed a novel PdCu catalyst with an ordered body-centered cubic (BCC) structure, enabling precise control over Pd nuclearity to optimize selectivity. Using a facile polyol synthesis method, we modulated the Pd coordination environment, reducing the Pd–Pd coordination number from 3 (disordered face-centered cubic, FCC) to 0 (ordered BCC), thereby achieving full isolation of Pd by the surrounding Cu atoms. This structural transformation enhances hydrogen spillover and weakens ethylene adsorption, resulting in superior activity for the selective hydrogenation of acetylene to ethylene. The ordered PdCu supported on Al2O3 (o-PdCu/Al2O3) achieved a 99% acetylene conversion with an 84.5% ethylene selectivity at near-room temperature. This work highlights the importance of controlling atomic-scale nuclearity in metal catalysts and provides a promising strategy for improving the catalytic efficiency and selectivity in industrially significant processes.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2025
·
IF 14.3
Feilong Jiang,Lu Yang,Dingshan Liang,Jiasi Luo,Kangjie Chu,Chengxia Wei,Qiming Zhuang,Zongyuan Li,Fuzeng Ren
Refractory high-entropy alloys (RHEAs) are celebrated for their exceptional yield strength and high-temperature stability, yet their wear performance remains insufficient. The wear behavior of these materials is largely governed by their deformation mechanisms and microstructural evolution during sliding. In this study, we synthesized an ultrafine-grained TiZrNbMoTa RHEA featuring a dual-phase microstructure comprising body-centered cubic (BCC) and hexagonal close-packed (HCP) phases. This unique microstructure enhances wear resistance via the in-situ formation of gradient nanostructured layers at room temperature (RT) and fish-scale-like amorphous-crystalline nanocomposite oxide layers at 600 °C during dry sliding. The RHEA exhibits wear rates of 1.15 × 10 −4 mm 3 /(N m) at RT and 9.85 × 10 −6 mm 3 /(N m) at 600 °C. At RT, a ∼3 µm thick subsurface deformation layer developed, with the upper 1.2 µm displaying distinct nanolayered structures, while the underlying grains bent and elongated along the sliding direction. At 600 °C, a protective fish-scale-like amorphous-crystalline nanocomposite oxide layer formed on the worn surface, thereby preventing direct contact between the alloy and the counterbody. This study presents a novel approach to enhancing wear resistance in BCC-HCP dual-phase TiZrNbMoTa RHEA, highlighting the critical role of nanostructured surface layers in enhancing performance under sliding conditions.
研究领域:
材料科学
·
金属学与冶金工程
·
表面工程
·
摩擦学
·
纳米材料
✓ 已验证
产品关联
DOI
高影响因子
Advanced Quantum Technologies
·
2023
·Vol. 6
·期 12
·2300213
·
IF 4.4
Lingyong Zeng,Jie Zhan,Mebrouka Boubeche,Kuan Li,Longfu Li,Peifeng Yu,Kangwang Wang,Chao Zhang,Kui Jin,Yan Sun,Huixia Luo
X-ray powder diffraction, electrical resistivity, magnetization, and thermodynamic measurements are conducted to investigate the structure and superconducting properties of TiHfNbTaMo, a novel high-entropy alloy possessing a valence electron count (VEC) of 4.8. The TiHfNbTaMo HEA is discovered to have a body-centered cubic structure (space group I m 3 ¯ m $Im\bar{3}m$ ) with lattice parameters a = 3.445 (1) Å and a microscopically homogeneous distribution of the constituent elements. This material shows type-II superconductivity with T c = 3.42 K, lower critical field µ 0 H c1 (0) = 22.8 mT, and upper critical field µ 0 H c2 (0) = 3.95 T. Low-temperature specific heat measurements show that the alloy is a conventional s-wave type with a moderately coupled superconductor. First-principles calculations show that the density of states (DOS) of the TiHfNbTaMo alloy is dominated by hybrid d orbitals of these five metal elements. Additionally, the TiHfNbTaMo HEA exhibits three van Hove singularities. Furthermore, the VEC and the composition of the elements (especially the Nb elemental content) affect the T c of the bcc-type HEA.
研究领域:
材料科学
·
凝聚态物理
·
超导物理
·
合金设计
·
量子材料
✓ 已验证
DOI
高影响因子
POWDER METALLURGY
·
2022
·
IF 2.228
Ying Zhang,Meng Xiao,Yi-min Zhou,Yi-fu Shen
The eutectic FeNiCoCrTi0.6Nb0.4 high-entropy alloy coating (HEAC) is annealed in Argon at 450°C, 850°C and 1050°C to investigate the thermal stability. The results show that annealed coatings are all composed of BCC solid solution and Laves phase with no production of new phases. The fine eutectic cells can be maintained at a higher temperature in that continuous intracellular coarsening does not occur until annealing at 1050°C. With the increase of annealing temperature, the microhardness and wear resistance of FeNiCoCrTi0.6Nb0.4 coating increase first and then decrease slightly. Especially, the microhardness of FeNiCoCrTi0.6Nb0.4 annealed at 1050°C is only 6.03% lower than that of unannealed one, and the wear rate is only 10.70% higher than that of unannealed one, which strongly indicates that eutectic FeNiCoCrTi0.6Nb0.4 HEAC has excellent thermal stability and can be well applied in high-temperature environments.
研究领域:
材料科学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Xingzhan Yuan,Shi Hong,Jing Wang,Bing Ma,Yifan Zhang,Man Niu,Laima Luo,Yucheng Wu
In this study, we propose a model to evaluate the ductile-to-brittle transition (DBT) of W based alloy using small tensile test and dislocation density measurement. The new model is built upon the high correlation between the DBT and the dislocation multiplication. Compared the measured results from the typical testing methods such as small tensile test, three-point bending test, it reveals that the new model is close to the bending test results. Interestingly, the equivalent transition temperature (ETT) of W-Y 2 O 3 alloy measured by three-point bending test and the new model is lower than that of pure W. The effect of grain boundary and Y 2 O 3 particles on DBT were discussed, and the lower transition temperature of W-Y 2 O 3 alloy is attributed to the easier dislocation multiplication near grain boundary as well as the increase of small angle grain boundary.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Jin Li,Hui Wang,Jingbo Xu,Shengyue Wu,Mengmeng Han,Jianfei Li,Qianqian Wang,Zhiming Ge
Discoid-reconstituted high-density lipoprotein (d-rHDL) is advantageous for tumor-targeted drug delivery due to its small size, long circulation, and efficient internalization into cancer cells. Nevertheless, an allosteric reaction catalyzed by serum lecithin-cholesterol acyltransferase (LCAT) may cause drug leakage from d-rHDL and reduce its targeting efficiency. Conversely, similar “structural weakening” catalyzed by acyl-coenzyme A-cholesterol acyltransferase (ACAT) inside tumor cells can stimulate precise intracellular drug release. Therefore, we synthesized and characterized a pH-sensitive n-butyraldehyde bi-cholesterol (BCC) to substitute for cholesterol in the d-rHDL particle, and bovine serum albumin (BSA) was used as the targeting agent. This dual pH- and ACAT-sensitive d-rHDL (d-d-rHDL) was small with a disk-like appearance. Morphological transformation observation, in vitro release assays, and differences in internalization upon LCAT treatment confirmed that BCC effectively inhibited the remodeling behavior and enhanced the tumor-targeting efficiency. The accumulation of d-d-rHDL in HepG2 cells was significantly higher than that in LO2 cells, and accumulation was inhibited by free BSA. The pH sensitivity was verified, and d-d-rHDL achieved efficient drug release in vitro and inside tumor cells after exposure to acidic conditions and ACAT. Confocal laser scanning microscopy demonstrated that d-d-rHDL escaped from lysosomes and became distributed evenly throughout cells. Moreover, in vivo imaging assays in a tumor-bearing mouse model demonstrated tumor-targeting properties of d-d-rHDL, and paclitaxel-loaded d-d-rHDL showed strong anticancer activity in these mice. This dual-sensitive d-d-rHDL thus combines structural stability in plasma and an intracellular pH/ACAT-triggered drug release to facilitate inhibition of tumor growth.
研究领域:
药学
·
癌症研究
·
药物递送系统
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）