检索结果-内蒙古大学图书馆

Ultra-Fine Grained Tungsten Heavy Alloy Prepared by High-Pressure Spark Plasma Sintering

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Zhang, Shuaihao Ji, Wei Zhu, Qiqi Li, Qiunan Wang, Weimin Fu, Zhengyi State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Hanjiang Hongyuan Xiangyang Silicon Carbide Special Ceramics Co. Ltd. Xiangyang441000 China

Tungsten heavy alloy (WHA) is an ideal material employed for kinetic energy penetrators due to its high density and excellent mechanical properties. However, it is difficult to obtain ultra-fine grained tungsten alloy with excellent properties by traditional powder metallurgy method because of severe grain growth at high sintering temperature with long soaking time. In this study, highly dense 93W-5.6Ni-1.4Fe (wt.%) WHA was successfully fabricated at low temperature of 950 °C with high pressure of 150 MPa by spark plasma sintering. The as-sintered tungsten alloy possesses high relative density (98.6%), ultra-fine grain size (271 nm) and high dislocation density (2.6×1016 m-2 ), which results in excellent properties such as high hardness (1079 HV1). © 2022, The Authors. All rights reserved.

关键词： Spark plasma sintering

Machine Learning for Battery Research

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Zhao, Yan Wei, Zheng He, Qiu International School of Materials Science and Engineering State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Hubei430070 China The Institute of Technological Sciences Wuhan University Wuhan Hubei430072 China

Batteries are vital energy storage carriers in industry and in our daily life. There is continued interest in the developments of batteries with excellent service performance and safety. Traditional trial-and-error experimental approaches have the limitations of high-cost and low-efficiency. Atomistic computational simulations are relatively expensive and take long time to screen massive materials. The rapid development of machine learning (ML) has brought innovations in many fields and has also changed the paradigm of the battery research. Numerous ML applications have emerged in the battery community, such as novel materials discovery, property prediction, and characterization. In this review, we introduced the workflow of ML, where the task, data, feature engineering, and evaluation were involved. Several typical ML models used in batteries were highlighted. In addition, we summarized the applications of ML for the discovery of novel materials, and for property and battery state prediction. The challenges for the application of ML in batteries were also discussed. © 2022, The Authors. All rights reserved.

关键词： Machine learning

The Effects of Diatom Frustules Shapes and Purity on the Performance of Diatom-Based Lithium Ion Silicon Carbon Anode materials

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Liu, Yuhang Ren, Zijie Zhou, Liang Jiang, Yuqian Gao, Huimin An, Qinyou Xu, Longhua School of Resources and Environmental Engineering Wuhan University of Technology Hubei Wuhan430070 China Key Laboratory of Hubei Province for Mineral Resources Processing Environment Wuhan430070 China State Key Laboratory of Environment-friendly Energy Materials Sichuan Mianyang621010 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China Southwest University of Science and Technology China

Diatomite has been widely studied as a silicon source. Three kinds of diatomite with different diatom frustules or different purities were reduced to porous silicon. The porous silicon coated carbon was prepared into positive electrode materials for battery cycle performance test. The test results showed that the Si/C composites anode material obtained by the reduction of diatomite with high purity of SiO2 has a high initial capacity, 2491mAhg-1, while that with low SiO2 purity is only 1412mAhg-1. The capacity retention rate of Si/C material prepared by columnar diatomite structure is higher than that of discoid diatomite. The battery made of high purity diatomite with discoid diatom has serious attenuation after 40 cycles. It could only retain 1/10 of the initial capacity, while the attenuation of the battery prepared by cylindrical diatomite is much better. The reason was that the specific surface area of macro porous silicon was much smaller than that of mesoporous silicon and less lithium ions were consumed in the irreversible process of forming solid electrolyte membrane for the first time. It could also be known that an appropriate amount of impurities in porous silicon can effectively reduce the volume expansion of silicon during the battery charge and discharge. The main reason was that the impurities occupied the internal space to alleviate the volume expansion of silicon or the excess carbon was coated on the impurities. © 2022, The Authors. All rights reserved.

关键词： Lithium-ion batteries

Local amorphization in boron carbide at finite temperature: Strategies toward improved ductility

学校读者我要写书评

暂无评论

Physical Review B 2021年第13期104卷 134105-134105页

作者： Jun Li Qi An Lisheng Liu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Chemical and Materials Engineering University of Nevada-Reno Reno Nevada 89557 USA

Boron carbide (B4C) is superhard, but its engineering applications are limited by the abnormal brittle failure arising from amorphous shear band formation. Mitigating the local amorphization is essential to improve the ductility of B4C. Here, we carried out ab initio molecular dynamics (AIMD) simulations to examine the response of B4C to shear along two plausible slip systems (001)/[100] and (111)/[112¯] at finite temperature. We found that the icosahedra of B4C gradually deconstruct at finite temperature, resulting in local amorphization, thereby giving rise to a lower stress barrier than that of density functional theory simulations at zero temperature. The deconstruction of the icosahedral clusters arises from the interaction with the neighboring chains. The failure mechanism at the finite temperature suggested that the local amorphization can be suppressed by altering the structure of the 12-atom icosahedron and the 3-atom chain of B4C. To demonstrate this, we replaced the B11CP icosahedron in B4C with B12 icosahedron to form boron-rich boron carbide (B13C2) and then performed the same shear deformations. We found that local amorphization significantly decreases, which results from the modified icosahedral interaction. We also altered the 3-atom C-B-C chain to the 2-atom P-P chain and found that the accumulated shear stress can be released through icosahedral slipping, which is achieved by breaking the chains. The icosahedral slipping then prevents the destruction of icosahedra under shear deformations, expected to improve the ductility. Our results demonstrate two design strategies toward improved ductility of B4C: (1) boron enrichment can alleviate amorphous shear band formation in boron carbide, and (2) altering the 3-atom chain to a 2-atom chain and meanwhile decreasing the strength of the chain to make it less stable than the icosahedron cage may lead to an icosahedral-slipping-dominated mechanism, thereby avoiding icosahedral fracture.

关键词： material failure Mechanical & acoustical properties Phase transitions Shear deformation

Preparation and dielectric properties of high reliability Nano-BaTiO3 Co-doped with Tm2O3 and MgO for BME-MLCC application

学校读者我要写书评

暂无评论

Ceramics International 2025年

作者： Liu, Haizhou Wang, Zhen Wu, Jianjian Guo, Qinghu Yao, Zhonghua Liu, Hanxing Hao, Hua State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Material Science and Engineering International School of Material Science and Engineering Wuhan University of Technology Wuhan 430070 China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Xianhu Hydrogen Valley Foshan 528200 China

BaTiO3 has become the most widely used material in MLCC due to its excellent electrical properties. In this work, BaTiO3-x %Tm2O3 (x = 1, 3, 5, 7) and BaTiO3-5 %Tm2O3-y %MgO (y = 0.2, 0.4, 0.6, 0.8) ceramics were prepared by solid-state method in reducing atmosphere and reduction resistance mechanism and dielectric properties of them were investigated. It is confirmed that the Tm³⁺ ion substitutes the Ti⁴⁺ site and significantly improves the reduction resistance of BaTiO3 ceramics when x ≥ 3 with resistivity up to 10¹⁰ Ω•cm. The grain size of BaTiO3-5 %Tm2O3-y %MgO ceramics is reduced to 176 nm, which is beneficial to increase bias stability. The formation of the “core-shell” structure improves the dielectric temperature stability of BaTiO3-based ceramics and a series of X7R (−55 °C–125 °C, temperature coefficient of capacitance (TCC) ≤ ±15 %) ceramics were obtained when x = 5 and y = 0.2–0.6. When x = 5, y = 0.4, the dielectric constant at room temperature is 1610 with a low dielectric loss of 0.009. Combining XPS and TSDC analyses, the reduction resistance mechanism of BaTiO3-5 %Tm2O3-y%MgO ceramics is attributed to the formation of defect dipoles, [2TmTi^′−VO^··] and [MgTi^″−VO^··], due to the cooperation of acceptor ions.

关键词： Anti-reduction BaTiO3 Dielectric temperature stability Resistivity

Effective Strengthening and Toughening in Zn-1mg Alloy with Bimodal Grain Structure Achieved by Conventional Extrusion

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Li, Ruimin Ding, Yutian Zhang, Hongfei Lei, Jian Shen, Yue State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology Lanzhou730050 China School of Materials Science and Engineering Lanzhou University of Technology Lanzhou730050 China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology School of Material Science and Engineering Lanzhou University of Technology No.287 langongping Road Qilihe district Lanzhou China

To better solve the problem that the inadequate mechanical performance of pure Zn and its as-cast alloys restricted the further clinical implant applications owing to its coarse grain size and HCP structure, some attempts at microstructure manipulation have been made by researchers. Interestingly, architecting heterogeneous structures is a promising strategy for overcoming the trade-off between strength and ductility in metallic materials. Herein, we reported a simple extrusion pathway for fabricating Zn-1Mg alloy with bimodal structure. Results revealed that the developed Zn alloy exhibited microstructural heterogeneities, including both bimodal grain structure and reforcement phase particles, which endowed the Zn-1Mg alloy with a satisfactory combination of yield strength (YS) of ~289 MPa, ultimate tensile strength (UTS) of ~320 MPa and fracture elongation (EL) of ~32%, superior to most Zn alloys reported so far. The strengthening-toughening mechanisms were systematically analyzed and the quantitative relationships between the yield strength and grain structure with a bimodal size distribution, as well as the second phase were established in this work. Additionally, the microstructure of the as-cast alloy consisted of the primary α- Zn dendrites and a three-component eutectic structure: α- Zn+Mg 2 Zn 11 +MgZn 2 . In as-extruded alloy, broken phase particles were effective sites for dynamic recrystallized (DRXed) grains nucleation via particle-stimulated nucleation (PSN) mechanism. This work would provide valuable insights for the design and production of high strength-ductility zinc alloys. © 2022, The Authors. All rights reserved.

关键词： Extrusion

Improved dielectric properties and anti-reducing mechanism of Er/Mg Co-doped BaTiO3-based ceramics produced in reducing atmosphere

学校读者我要写书评

暂无评论

Ceramics International 2025年

作者： Zeng, Manting Liu, Xingzhong Hao, Hua Yao, Zhonghua Liu, Hanxing State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Material Science and Engineering International School of Material Science and Engineering Wuhan University of Technology Wuhan430070 China Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Xianhu Hydrogen Valley Foshan528200 China

BaTiO3-1.6MnO2-xEr2O3 ceramics (abbreviated as BMT-xEr) and BaTiO3-1.6MnO2-3Er2O3-xMgO ceramics (abbreviated as BEMT-xMg) were prepared under a reducing atmosphere by solid-state synthesis method in this work. The effects of Er/Mg co-doping on phase transformation, microstructure, dielectric properties, and defect were systematically investigated. Research shows that Er-doping reduces the Curie temperature and increases the dielectric constant of BaTiO3 ceramics at low temperatures. Mg-doping refines the grain size and makes the grain size distribution more uniform, which is an important reason for the enhanced bias stability. The substitution of Mg at the B-site generates additional oxygen vacancies which capture free electrons and simultaneously forms defect dipoles. The anti-reducing properties are improved by reducing the carrier concentration. The synergistic effect of co-doping forms defect dipoles such as [MgTi″‐2ErBa∙], [MgTi″‐VO∙∙] and [2ErTi′‐VO∙∙] to enhance dielectric relaxation behavior which is considered to be the reason for the improved dielectric temperature stability. When x = 0.4, optimized dielectric ceramics are obtained with Ε25°C = 1820, tanδ = 0.009, resistivity of 1.0 × 1011 Ω·cm, which meets the EIA X7R standard (−55 °C - 125 °C, TCC ≤ ± 15 %). © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Dielectric properties of solids

Gradient Vertical Morphology Engineering Enabling 18.51% Efficient All-Polymer Solar Cells through Sequential Deposition Strategy

学校读者我要写书评

暂无评论

materials Today Energy 2025年

作者： Xiaojie Ren Yi Jin Rui Hu Di Xie Xiang Huang Hairun Wen Yimeng Sun Zhixiong Huang Wenchao Huang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 China

All-polymer solar cells (all-PSCs) have broad application prospects in industrial production because of their superior stability and mechanical durability. However, poor compatibility between donor and acceptor materials, associated with disordered chain entanglement, limits the formation of the optimal vertical morphology in the active layer. In this paper, a gradient vertical structure of donor/bulk-heterojunction (BHJ)/acceptor is developed by fabrication of PM6:PY-IT (binary) BHJ sandwiched by layers of PBQx-TCl (bottom) and PY-V-γ (top). As a result, the devices based on the structure of PBQx-TCl/binary/PY-V-γ show more balanced charge mobility and reduced charge recombination, achieving a power conversion efficiency (PCE) of 18.51%, which is significantly higher than that of the control groups: pristine binary (17.34%), PBQx-TCl/binary (18.01%), and binary/PY-V-γ (17.78%). This work provides an effective and facile strategy for constructing gradient vertical morphology in the all-PSCs.

关键词：

synthesis of Cr_2AlC from Elemental Powders with Modified Pressureless Spark Plasma Sintering

学校读者我要写书评

暂无评论

Journal of Wuhan University of technology(materials Science) 2019年第2期34卷 287-292页

作者：葛梦妮 WANG Xiaofan LI Gaiye LU Chen 张建峰 TU Rong College of Mechanics and Materials Hohai University State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

We introduced a modified pressureless sintering strategy by SPS with a new T-shape die and tapered punches, which helps the evaporation of melted Al and reduces the sample sticking with the inner wall of the die. Thus, the die breaking risk in the sintering process or the de-molding process is avoided at all. At a low temperature and short holding time, a high purity of Cr_2 AlC was obtained in this SPS process from the optimization of different molar ratios of raw materials. Simultaneously, the high porosity of the as-obtained sample was also a distinguishing feature worth noticing. The reaction mechanism for this process was also discussed in detail. This study presented a new venue for future development of high purity "MAX" materials and others related materials by a modified pressureless sintering strategy.

关键词： pressureless spark plasma sintering Cr2AlC reaction mechanism