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Effects of Mo Content on the Microstructure and Mechanical Properties of Tinbzrmox High-Entropy Alloys

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SSRN 2022年

作者： Chen, Gengbiao Yan, Hongwei Wang, Zhe Wang, Kaiming Yves, Ngabonziza Irumva Tong, Yonggang College of Automotive and Mechanical Engineering Changsha University of Science and Technology Changsha410114 China Hunan Provincial Key Laboratory of Safety Design and Reliability Technology for Engineering vehicles Changsha University of Science and Technology Changsha Changsha410114 China School of Foreign Studies Changsha University of Science and Technology Changsha410114 China

The single-phase TiNbZrMox (x=0, 0.3, 0.5, 0.7, 1) high-entropy alloys (HEAs) were prepared by via arc melting. The relation between molybdenum, microstructure, mechanical properties and wear resistance was investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM), universal tensile tester, hardness tester, friction tester, and wear tester. The results showed that TiNbZrMox alloys were composed of a single BCC phase. With the increase of molybdenum, the grain size of the as-cast alloy decreased first and then increased, both the alloy strength and hardness were increased and compressive strain plasticity was decreased. TiNbZrMo0.5 exhibited has the best comprehensive performance with a yield strength of 1.0 GPa, compressive strength of 1.3 GPa, and hardness of 429 HV;compared with TiNbZrMo0, increased by 77.32%, 25.14%, and 70.24% respectively;and its specific wear rate decreased by 50%, while it’s compressive plasticity only decreased by 5%. © 2022, The Authors. All rights reserved.

关键词： Microstructure

The effect of creep on the lubrication property of rubber-plastic composite water-lubricated bearings

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The effect of creep on the lubrication property of rubber-pl...

International Conference on Transportation Information and safety (ICTIS)

作者： Xu Guo Xincong Zhou Bin Luo Qun Zou Yanhong Wang Jian Huang School of Transportation and Logistics Engineering Wuhan University of Technology Wuhan China State Key Laboratory of Maritime Technology and Safety Wuhan University of Technology Wuhan China China Ship Development and Design Center Wuha China School of Naval Architecture Ocean and Energy Power Engineering Wuhan University of Technology Wuhan China Reliability Engineering Institute Wuhan University of Technology Wuhan China

The deformation of water-lubricated bearings liner has a direct effect on lubrication properties. However, creep deformation is a key factor that has often been neglected in water-lubricated bearing design, manufacture, and operation. This paper investigated the creep deformation of rubber-plastic composites with different thicknesses. The creep effect on lubrication performance was also discussed. Creep tests were conducted using an electronic universal tensile tester. Based on the test results, the creep constitutive equation for rubber-plastic composites was determined. The lubrication model based on the creep constitutive equation was established to evaluate the water film pressure and thickness. The results showed that creep reduces the water film pressure and thickness of the water-lubricated stern bearing, and results in the loading region contraction. The shape contraction position of the water film shape in the outlet area shifts to the central position, and the depth of the contraction depression decreases. By reducing the thickness of the rubber-plastic composite, the water film pressure and thickness are increased. The shape of the water film in the outlet area shrinks and the position gradually shifts away from the center.

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Parametric Study on SUV-e-bike Collision for safety Test & Evaluation Regulations

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Parametric Study on SUV-e-bike Collision for Safety Test & E...

2021中国汽车工程学会年会暨展览会

作者： Liu Yu Wan Xinming Xu Wei Shi Liangliang Bai Zhonghao State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University State Key Laboratory of Vehicle NVH and Safety Technology China Automotive Engineering Research Institute Co. Ltd.

To explore the kinematics and injury response of the rider's head after the collision with the vehicle,and to determine the test and evaluation boundary for its *** accident involving an e-bike was reconstructed based on an automatic operation framework,then the reliability of the reconstruction model was verified from comparisons of rider's kinematics,the rest position of three participants,and injury with accident ***,a total of 1296 parametric cases were performed by the automatic operation framework,which was based on the validated model with a full factorial experimental design according to the collision boundary such as velocity,position,and angle from ***,a data set with 1005 valid cases were used to discuss the distribution patterns of the head's kinematics and injury response when colliding with the vehicle such as initial impacting time,linear and angular velocity,WAD,and also for head injury criteria(HIC).The results show that WAD is positively correlated with the size of the rider and vehicle *** head contact points on the vehicle are located before WAD2100,and WAD1100-1600 should be considered significant for riders' protection.92 % of the head impacting linear velocity are lower than 50 km/h,78 % is less than 40 km/*** collision angle of50-70° accounts for 62%,and the average angle of 5,50,95 are 57°,61°,62° *** subsystem impactor,within test area of WAD1000 ～2100 and with impacting velocity of 40 km/h and angle of 650 in current pedestrian protection regulation,seems to be applicable to the boundary of test and evaluation for SUV to e-bike riders.82% of cases with head initial collision time are less than 140 ms,and head injuries of e-bike riders mainly come from ground *** a preliminary exploration,distribution patterns of rider's kinematics and injury response in this article will provide data and theoretical support for formulation and revision of evaluation regulations an

关键词： e-bike rider parametrization kinematics and injury response test & evaluation regulations

A promising candidate for ising ferromagnetism of two- dimensional kagome V2O3 honeycomb monolayer

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arXiv

arXiv 2024年

作者： Subhan, Fazle Gao, Chuanhao Ali, Luqman Zhou, Yanguang Qin, Zhenzhen Qin, Guangzhao State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China Department of Pharmacology University of Virginia CharlottesvilleVA22903 United States Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong International Laboratory for Quantum Functional Materials of Henan School of Physics and Microelectronics Zhengzhou University Zhengzhou450001 China Research Institute of Hunan University in Chongqing Chongqing401133 China Greater Bay Area Institute for Innovation Hunan University Guangdong Province Guangzhou511300 China

Due to the low dimensionality in the quantization of the electronic states and degree of freedom for device modulation, two-dimensional (2D) ferromagnetism plays a critical role in lots of fields. In this study, we perform first-principles calculation to investigate the ising ferromagnetism and half-metallicity of kagome V2O3 monolayer. Based on the calculations using different functional, it is found that GGA-PBE gives a half-metallic band gap while the GGA+U gives a semiconductor narrow band gap (-1.1 meV), which shows quasi-half metallic nature. By studying the magnetic properties with LDA, GGA-PBE, and GGA+U, we get a robust ferromagnetic ground state, where the giant perpendicular magnetic anisotropy energy of -0.544 meV is achieved by applying the spin-orbit coupling (SOC) with GGA+U. Furthermore, by exploring the orbital contribution to the electronic bands and the magnetic crystalline anisotropy, it is uncovered that the 3d (V) orbitals contribute to the out-of-plane. The electronic band structure shows two flat bands (F1 and F2) and Dirac points (D1 and D2) which further confirm that kagome V2O3 ML can also be used for topological properties. Besides, the Curie temperature of the V2O3 ML is calculated to be 640 K by Metropolis Monte Carlo (MC) simulations. © 2024, CC BY-NC-ND.

关键词： Electronic properties

Experimental Study on Microstructure and Mechanical Properties of Dissimilar Cu/Al Welds by Hybrid Coaxial Blue-Ir Laser

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SSRN 2023年

作者： Zhang, Mingjun Zhang, Yuxuan Zhang, Jian Li, Heqing Cheng, Bo Wu, Xiang Zhou, Dianwu Mao, Cong Hu, Yongle Li, Wen Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment Changsha University of Science and Technology Changsha410114 China Institute of Metals College of Materials Science and Engineering Changsha University of Science & Technology Changsha410114 China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha410082 China Hunan SANY Tower lifting Machinery Co. Ltd. Changsha410600 China

A hybrid blue-infrared (IR) laser is proposed to weld 5052 Al with T2 Cu to investigate the impact of processing parameters on the quality of Cu/Al overlap joints in terms of microstructures, mechanical properties, and failure modes. The experiments show that combining an infrared laser and a blue laser enlarges an opening channel of weld and stabilizes the convention on edge of the weld pool, this eases the escapes of bubbles and prevents the formations of pores. When a hybrid coaxial blue-IR with a power less than 500 W is used, and the weld strengths of the specimens are increased significantly, while the plasticity is decreased slightly in comparison with the specimens welded by an infrared laser. When the power of the blue laser is increased to 800 W, the strength and plasticity of a lapped weld are decreased significantly. Moreover, the welds by an infrared laser were fractured in a mixed fracture mode When a hybrid coaxial blue-IR laser is used, the weld is ruptured by a ductile fracture and a brittle fracture when the blue laser power is lower 500W and over 800 W, respectively. © 2023, The Authors. All rights reserved.

关键词： Microstructure

Site Occupation Regulation of Eu2+ by the Introduction of (Bo3)3- Group Towards Full-Visible-Spectrum Emission in a Singly Doped KK2BaSr(PO4)2:Eu2+ Phosphor

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SSRN 2023年

作者： Xie, Guodong Si, Jiayong Li, Guihua Cai, Gemei Wang, Zhipeng Wang, Xiaojun College of Mechanical and Electrical Engineering Central South University of Forestry and Technology Hunan Changsha410004 China School of Materials Science and Engineering Central South University Hunan Changsha410083 China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Hunan Changsha410082 China Department of Physics Georgia Southern University StatesboroGA30460 United States

Efficient regulation of activator site occupation is crucial for developing white light phosphors with excellent luminous properties. Herein, we report the synthesis of new borophosphate K2BaSr(PO4)2-x(BO3)x:0.04Eu2+ phosphors via an anion groups substitution strategy. In the pristine sample, there are three different cationic sites (Ba2+, Sr2+, and K+) with differed coordination environment where Eu2+ can occupy the Ba2+ and/or Sr2+ sites. In the process of (BO3)3- partially substituting (PO4)3- units, owing to the effect of increased cation disorder generated from the difference in geometric configurations between the two anion groups, new emission band centering around 535 nm appears in the emission spectra. The intensity of this band increases as more (PO4)3- units are substituted by (BO3)3-, resulting in the phosphor emission tuned from blue to white by controlling the (BO3)3- concentration. This emission band can be attributed to the occupation of Eu2+ for K+ sites induced by cation disorder through the analysis of structural and photoluminescent properties and first-principles calculation. A phosphor-converted LED (pc-LED) has been successfully fabricated using the phosphor at the optimized compositions, K2BaSr(PO4)1.8(BO3)0.2:0.04Eu2+, and a 365 nm near-ultraviolet chip, exhibiting a color rendering index of 81.3 and a correlated color temperature of 7024 K. Our findings demonstrate the effectiveness of the anion group modulation for developing new high-performance LED phosphors. © 2023, The Authors. All rights reserved.

关键词： Phosphors

New β-type Ti-Zr-V-Nb alloys used for laser-based direct energy deposition: design, microstructure, and properties

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Materials Characterization 2022年 189卷

作者： Zhao, Zisong Wang, Cunshan Yu, Qun Song, Lijun Yang, Guang Zhang, Jingtao Key Laboratory of Materials Modification by Laser Ion and Electron Beams Dalian University of Technology Liaoning Dalian116024 China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan Provincial Key Laboratory of Intelligent Laser Manufacturing Hunan University Changsha410082 China School of Mechatronics Engineering Shenyang Aerospace University Liaoning Shenyang110136 China

To develop new titanium alloys for laser-based direct energy deposition, Ti-Zr-V-Nb alloys were designed from a basic Ti60.94Zr39.06 congruent composition alloyed with constant V content and varying Nb contents. The microstructure and properties of the alloys, fabricated by laser-based direct energy deposition, were systematically studied. The results show that all as-deposited alloys consist of near-equiaxed β grains with multiple orientations. The difference is that the lattice parameter of the phase enlarges and its grain size reduces with increasing Nb content, which leads to a continuous increase in hardness, strength, wear and corrosion resistance. But the ductility shows a reverse variation due to the combination of enhanced solid solution strengthening and dislocation strengthening. Owing to the combined effect of fluidity and spreadability of melt, the surface roughness firstly decreases and then increases with the increase of Nb content. The optimized alloy with 3.91 at.% Nb exhibits a good match of mechanical, tribological, and chemical properties compared with Ti60.94Zr39.06 congruent alloy, being a promising candidate used for laser-based direct energy deposition. © 2022 Elsevier Inc.

关键词： Titanium alloys

Biaxial strain modulated electronic structures of layered two-dimensional MoSiGeN4 Rashba systems

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arXiv

arXiv 2023年

作者： Li, Puxuan Wang, Xuan Wang, Haoyu Tian, Qikun Xu, Jinyuan Yu, Linfeng Qin, Guangzhao Qin, Zhenzhen International Laboratory for Quantum Functional Materials of Henan School of Physics and Microelectronics Zhengzhou University Zhengzhou450001 China Institute for Frontiers in Astronomy and Astrophysics Department of Astronomy Beijing Normal University Beijing100875 China National Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle Engineering Hunan University Changsha410082 China

The two-dimensional (2D) MA2Z4 family has received extensive attention in manipulating its electronic structure and achieving intriguing physical properties. However, engineering the electronic properties remains a challenge. Herein, based on first-principles calculations, we systematically investigate the effect of biaxial strains on the electronic structures of 2D Rashba MoSiGeN4 (MSGN), and further explore how the interlayer interactions affect the Rashba spin splitting in such strained layered MSGNs. After applying biaxial strains, the band gap decreases monotonically with increasing tensile strains but increases when the compressive strains are applied. An indirect-direct-indirect band gap transition is induced by applying a moderate compressive strain (2 orbital hybridized with N-pz orbital in the highest valence band plays a dominant role on the band evolution under biaxial strains, where the R→L evolution corresponds to the decreased Mo-dz2 orbital contribution. Our study highlights the biaxial strain controllable Rashba spin splitting, in particular the introduction and even the evolution of Lifshitz transition near Fermi surface, which makes the strained MSGNs as promising candidates for future applications in spintronic devices. Copyright © 2023, The Authors. All rights reserved.

关键词： Electronic structure

Practical Uncertainty Quantification for Space-Dependent Inverse Heat Conduction Problems Via Ensemble Physics-Informed Neural Networks

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SSRN 2023年

作者： Jiang, Xinchao Wang, Hu Wang, Xin Wen, Ziming Li, Enying State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha410082 China Beijing Institute of Technology Shenzhen Automotive Research Institute Shenzhen518000 China College of Mechanical & Electrical Engineering Central South University of Forestry and Technology Changsha410082 China

Inverse heat conduction problems (IHCPs) are problems of estimating unknown quantities of interest (QoIs) of the heat conduction with given temperature observations. The challenge of IHCPs is that it is usually ill-posed since the observations are noisy, and the estimations of QoIs are generally not unique or unstable, especially when there are unknown spatially varying QoIs. In this study, an ensemble physics-informed neural network (E-PINN) is proposed to handle function estimation and uncertainty quantification of space-dependent IHCPs. The distinctive characteristics of E-PINN are ensemble learning and adversarial training (AT). Compared with other data-driven UQ approaches, the suggested method is more than straightforward to implement and also achieves high-quality uncertainty estimates of the QoI. Furthermore, an adaptive active sampling (AS) strategy based on the uncertainty estimates from E-PINNs is also proposed to improve the accuracy of material field inversion problems. Finally, the proposed method is validated through several numerical experiments of IHCPs. © 2023, The Authors. All rights reserved.

关键词： Heat conduction