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Anisotropic tensile properties and high-cycle fatigue behavior of Ti6Al4V fabricated by single and dual laser-powder bed fusion

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Materials science and Engineering: A 2025年 941卷

作者： Guotai Li Peichen Hu Yuzhan Fan Ming Wu Mingjun Chen Tianyu Yu State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin Heilongjiang 150001 China Key Laboratory of Micro-systems and Micro-structures Manufacturing Ministry of Education Harbin Heilongjiang 150001 China Department of Computer Science KU Leuven 3001 Leuven Belgium Department of Mechanical Engineering KU Leuven 3001 Leuven Belgium

The development of multi laser-powder bed fusion (PBF) technology has significantly reduced the production time for large engine components. However, the impact of thermal effects and microstructural characteristics in the laser beam overlap region on the anisotropic mechanical behavior of metallic materials remains unclear. This study investigated the anisotropic tensile properties and high-cycle fatigue behavior of Ti6Al4V produced by both single laser-PBF (SL-PBF) and dual laser-PBF (DL-PBF). As-built DL-PBF samples exhibited high strength (1404 MPa) but low ductility (3.6 %). After heat treatment, the samples achieved a strength-ductility balance, with an ultimate tensile strength of 1089 MPa, and an elongation of 17.1 %. The mechanical properties of Ti6Al4V produced by DL-PBF were influenced by the α lath thickness, dislocation density and texture. The precipitation of small-angle grain boundaries during DL-PBF process was found to contribute to the strong anisotropy. Due to the influence of internal pore forming, the fatigue strength of the DL-PBF samples was lower than that of the SL-PBF samples. Pores in the dual-laser beam overlap region accelerated the fatigue crack propagation, resulting in a venation-like pattern. In contrast, cracks in the SL-PBF samples propagated in a circular pattern around internal pore. A high-speed camera was employed to capture the dual-laser beams dynamics during pore formation. This study provides a comprehensive analysis of the mechanical properties and pore formation mechanisms in the DL-PBF process.

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Pre-Chirper Free Nonlinear Fiber Amplifier Generating Tunable Picosecond Pulses for Coherent Anti-Stokes Raman Imaging

Pre-Chirper Free Nonlinear Fiber Amplifier Generating Tunabl...

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Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim)

作者： Jiaying Li Jiamei Wu Kangwen Yang Qiang Hao Minbiao Ji Ming Yan Kun Huang Heping Zeng Shanghai Key Laboratory of Modern Optical System and Engineering Research Center of Optical Instrument and System Ministry of Education School of Optical Electrical and Computer Engineering University of Shanghai for Science and Technology Shanghai China State Key Laboratory of Surface Physics and Department of Physics Human Phenome Institute Multiscale Research Institute of Complex Systems Academy for Engineering and Technology Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) Fudan University Shanghai China State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai China Chongqing Institute of East China Normal University Chongqing China Jinan Institute of Quantum Technology Jinan China

A pre-chirper free, core-pumped nonlinear fiber amplifier was demonstrated to generate parabolic pulse with spectral bandwidth of 53 nm, these pulses were filtered and passively synchronized for conducting coherent an...

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SOT-MRAM-based true in-memory computing architecture for approximate multiplication

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Chip 2025年第2期4卷

作者： Song, Min Tang, Qilong Ouyang, Xintong Duan, Wei Xu, Yan Zhang, Shuai You, Long Key Laboratory of Intelligent Sensing System and Security of the Ministry of Education Hubei Key Laboratory of Micro-Nanoelectronic Materials and Devices School of Microelectronics Hubei University Wuhan430062 China School of Integrated Circuits Huazhong University of Science and Technology Wuhan430074 China

The in-memory computing (IMC) paradigm emerges as an effective solution to break the bottlenecks of conventional von Neumann architecture. In the current work, an approximate multiplier in spin-orbit torque magnetoresistive random access memory (SOT-MRAM) based true IMC (STIMC) architecture was presented, where computations were performed natively within the cell array instead of in peripheral circuits. Firstly, basic Boolean logic operations were realized by utilizing the feature of unipolar SOT device. Two majority gate-based imprecise compressors and an ultra-efficient approximate multiplier were then built to reduce the energy and latency. An optimized data mapping strategy facilitating bit-serial operations with an extensive degree of parallelism was also adopted. Finally, the performance enhancements by performing our approximate multiplier in image smoothing were demonstrated. Detailed simulation results show that the proposed 8 × 8 approximate multiplier could reduce the energy and latency at least by 74.2% and 44.4% compared with the existing designs. Moreover, the scheme could achieve improved peak signal-to-noise ratio (PSNR) and structural similarity index metric (SSIM), ensuring high-quality image processing outcomes. © 2025 The Author(s)

关键词： MRAM devices

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Dzyaloshinskii-Moriya anisotropy effect on field-induced magnon condensation in the kagome antiferromagnet α−Cu3.26Mg0.74(OH)6Br2

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Physical Review B 2021年第24期104卷 245107-245107页

作者： Ying Fu Jian Chen Jieming Sheng Han Ge Lianglong Huang Cai Liu Zhenxing Wang Zhongwen Ouyang Xiaobin Chen Dapeng Yu Shanmin Wang Liusuo Wu Hai-Feng Li Le Wang Jia-Wei Mei Institute of Applied Physics and Materials Engineering University of Macau Avenida da Universidade Taipa Macau 999078 China Shenzhen Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology Shenzhen 518055 China Department of Physics Southern University of Science and Technology Shenzhen 518055 China Wuhan National High Magnetic Field Center and School of Physics Huazhong University of Science and Technology Wuhan 430074 China School of Science and State Key Laboratory on Tunable Laser Technology and Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System Harbin Institute of Technology Shenzhen 518055 China Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and Technology Shenzhen 518055 China

We performed a comprehensive electron spin resonance, magnetization, and heat capacity study on the field-induced magnetic phase transitions in the kagome antiferromagnet α−Cu3.26Mg0.74(OH)6Br2. With the successful preparation of single crystals, we mapped out the magnetic phase diagrams under the c axis and ab-plane directional magnetic fields B. For B∥c, three-dimensional (3D) magnon Bose-Einstein condensation (BEC) is evidenced by the power law scaling of the transition temperature, Tc∝(Bc−B)2/3. For B∥ab, the transition from the canted-antiferromagnetic state to the fully polarized state is a crossover rather than a phase transition, and the characteristic temperature has a significant deviation from 3D BEC scaling. The different behaviors of the field-induced magnetic transitions for B∥c and B∥ab could result from the Dzyaloshinkii-Moriya (DM) interaction with the DM vector along the c axis, which preserves the c-axis directional spin rotation symmetry and breaks the spin rotation symmetry when B∥ab. Our findings have the potential to shed light on the investigations of magnetic anisotropy on the field-induced magnon BEC in a quantum antiferromagnet.

关键词： Critical field Dzyaloshinskii-Moriya interaction Magnetism Kagome lattice

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Excellent Energy Storage Properties in Zro2 Toughened Bst-Based Relaxor Ferroelectric Ceramics Via Multi-Scale Synergic Regulation

SSRN

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SSRN 2023年

作者： Yang, Fan Bao, Yizheng Zeng, Biao Wu, Jiyue Li, Xin Sun, Yiyang Chen, Ying Wang, Genshui Key Laboratory of Inorganic Functional Materials and Devices Shanghai Institute of Ceramics Chinese Academy of Sciences 1295 Dingxi Road Shanghai200050 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China The State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai200050 China National Key Laboratory of Materials for Integrated circuits Shanghai Institute of Micro-system and Information Technology Chinese Academy of Sciences 865 Changning Road Shanghai200050 China

Lead-free ceramic capacitors offer ultrahigh power density and ultrafast discharging rates, making them critical energy storage components for advanced pulsed power systems. However, the greatest obstacle to broader applications remains the relatively low energy storage density. In this study, a relaxor ferroelectric ceramic based on (0.6-x)Ba0.55Sr0.45TiO3-0.4Bi0.5Na0.5TiO3-xSrZrO3 ((0.6-x)BST-0.4BNT-xSZ) is prepared using the tape casting method, resulting in an excellent energy density (Wrec ≈ 10.0 J cm-3) and high energy storage efficiency (η ≈ 91%). The solid solution of linear dielectrics SrZrO3 synergistically regulates both relaxor properties and breakdown strength. The variation of relaxor property was explored utilizing New Glass model and the multi-polarization model, with confirmation provided by piezoresponse force microscopy. Furthermore, the breakdown strength could be attributed to improvements in electric insulation and the widening of the bandgap. As SZ content increases, the in-situ emergence of the second phase ZrO2, accompanied by a martensitic transformation, not only improves the fracture toughness of ceramics but also serves to elongate the breakdown path. Encouragingly, 0.4BST-0.4BNT-0.2SZ also achieves excellent temperature stability (-95-125 ℃), frequency stability (1-1000 Hz), cycling reliability (1-106 cycles), and great charging-discharging properties. This multiscale synergic regulation strategy plays a guiding role in the screening of high-performance energy storage dielectric materials. © 2023, The Authors. All rights reserved.

关键词： Ductile fracture

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Emission-Enhanced High-Performance Al2o3-Ce: (Y, Tb)Ag Composite Ceramic Phosphors for High-Brightness White Led/Ld Illumination

SSRN

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SSRN 2022年

作者： Tian, Yanna Chen, Jie Yi, Xuezhuan Jiang, Renjie Lin, Hui Tang, Yanru Zhou, Shengming Laboratory of Micro-Nano Optoelectronic Materials and Devices Key Laboratory of Materials for High-Power Laser Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai201800 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 United States Shanghai Tech University Shanghai201210 China Engineering Research Center of Optical Instrument and System University of Shanghai for Science and Technology Shanghai200093 China

Owing to their excellent thermal robustness, high light saturation threshold, and high luminous efficiency, Al 2 O 3 -Ce doped garnet composite ceramic phosphors (CCPs) have attracted extensive attention for applications in laser illumination. In this study, we report the fabrication of high-performance Al 2 O 3 -Ce:(Y, Tb) 3 Al 5 O 12 CCPs via a solid-state reaction. The promoted absorption of Ce 3+ by blue light due to the bidirectional energy transfer process between Ce 3+ and Tb 3+ was discovered in Al 2 O 3 -Ce:(Y, Tb)AG, which can effectively enhance the yellow light emission intensity and adjust the correlated color temperature (CCT). Based on this effect, Al 2 O 3 –Ce: (Y 0.9 Tb 0.1 ) 3 Al 5 O 12 CCPs show the best performance in thermal quenching and luminous efficiency;for example, its luminous efficiency at 450 K droops by 17% from the initial luminous efficiency, and its luminescence efficiency reaches 248.7 lm/W, when driven by 2.236 W of incident laser power. In addition, compared to the Al 2 O 3 -Ce: YAG CCPs, the CCT of the Al 2 O 3 –Ce: (Y 0.8 Tb 0.2 ) 3 Al 5 O 12 CCPs decreased by 3800 K under the excitation of LD, which is of great significance for realizing the warm white-light illumination. © 2022, The Authors. All rights reserved.

关键词： Phosphors

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A Practical and High-Performance Nitrogen Dioxide Gas Sensor that Can Be Rapidly Mass-Produced Based on Gallium Nitride Quantum Dots Film

SSRN

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SSRN 2022年

作者： Han, Dan Chen, Yi Li, Donghui Dong, Hailiang Xu, Bingshe Sang, Shengbo He, Xiuli Shanxi Key Laboratory of Micro Nano Sensors & Artificial Intelligence Perception College of Information and Computer Taiyuan University of Technology Taiyuan030024 China Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education Taiyuan030024 China Key Laboratory of Interface Science and Engineering in Advanced Materials Taiyuan University of Technology Ministry of Education Taiyuan030024 China State Key Laboratory of Transducer Technology Aerospace Information Research Institute Chinese Academy of Sciences Beijing100190 China Shanxi Research Institute of 6D Artificiat Intelligence Biomedical Science Taiyuan030024 China

Gallium nitride (GaN) has some challenges for gas sensing, such as high detection lower limit (LOD) or controlling the epitaxy of nanostructures. To address these issues, we exclusively designed a device to enhance the gas interaction capabilities of GaN quantum dots (QDs) film fabricated by metal-organic chemical vapor deposition (MOCVD). The GaN QDs film gas sensor exhibited a low LOD (5 ppb) to NO2 at room temperature (RT), which has much superior gas performance than other GaN-based sensors. The results manifest that many ultra-small QDs around 2 nm in diameter are stacked to form QDs of larger size, and confirm the existence of vacancies. The sensor displays a ultra-high electron mobility of 1237.37 cm2 V−1s−1, demonstrate that great shallow donor impurities in GaN QDs film that ionize easily at RT, which is greatly beneficial for gas sensing. The sensing mechanisms were analyzed based on its abundant active sites, ultrahigh carrier mobility, high surface energy and chemical activity, grain boundary barrier and good electrical conductivity. Moreover, the sensor processes high selectivity, repeatability, stability and reusability based on MOCVD technology which can realize precise control of structure, morphology and surface energy level, which is expected to achieve rapid industrialization. © 2022, The Authors. All rights reserved.

关键词： Gallium nitride

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Giant negative ECE near room temperature and large positive ECE of CoFe 2 O 4 -BiFeO 3 /P(VDF-TrFE) sandwich flexible films

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Applied Surface science 2025年 707卷

作者： Xiang Lv Lingfang Xu Yalong Ge Tian Liang Ronghua Qin Changping Yang Key Laboratory of Intelligent Sensing System and Security of the Ministry of Education Hubei Key Laboratory of Micro-Nanoelectronic Materials and Devices School of Microelectronics Hubei University Wuhan 430062 China Hubei Provincial Key Laboratory of Green Materials for Light Industry Hubei University of Technology Wuhan 430062 China Faculty of Materials Science and Engineering Taiyuan University of Science and Technology Taiyuan 030027 China

The electrocaloric effect (ECE) represents an eco-friendly, solid-state cooling technique utilizing a safe and potent electric field to facilitate the refrigeration process. This research demonstrates that incorporating CoFe 2 O 4 (CFO) and BiFeO 3 (BFO) at a 1:1 mass ratio into P(VDF-TrFE) results in notable giant negative ECE at near room temperature and positive ECE in sandwiched composite films. With a 5 wt% addition of CFO and BFO, the composite films exhibited giant adiabatic temperature changes of 11.3 K at 374.4 K and −24 K at 316 K. Using the Landau model, we confirmed the occurrence of both positive and negative ECEs. We predicted an adiabatic temperature change as high as −37.2 K at an electric field of 120 MV m −1 . The exceptional performance of the flexible, sandwiched composite films is attributed to their optimized microstructure and the strengthened local field around the dipoles, a result of the conductive CoFe 2 O 4 and BiFeO 3 nanoparticles. These dual-functional cooling films provide a means to boost the ECE in flexible materials, holding significant promise for applications in solid-state refrigeration tailored for flexible electronics. Future applications of the composite films may extend to various scenarios beyond the known multiferroic properties of BiFeO 3 and the magnetic characteristics of CoFe 2 O 4 .

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Thermal characterization of GaN heteroepitaxies using ultraviolet transient thermoreflectance

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Chinese Physics B 2019年第6期28卷 105-109页

作者： Kang Liu Jiwen Zhao Huarui Sun Huaixin Guo Bing Dai Jiaqi Zhu 1Ministry of Industry and Information Technology Key Laboratory of Micro-Nano Optoelectronic Information System Harbin Institute of TechnologyShenzhen 518055China Center for Composite Materials and Structures Harbin Institute of TechnologyHarbin 150080China Science and Technology on Monolithic Integrated Circuits and Modules Laboratory Nanjing Electronic Devices InstituteNanjing 210016China

Thermal transport properties of GaN heteroepitaxial structures are of critical importance for the thermal management of high-power GaN electronic and optoelectronic devices. Ultraviolet(UV) lasers are employed to directly heat and sense the GaN epilayers in the transient thermoreflectance(TTR) measurement, obtaining important thermal transport properties in different GaN heterostructures, which include a diamond thin film heat spreader grown on GaN. The UV TTR technique enables rapid and non-contact thermal characterization for GaN wafers.

关键词： GaN heteroepitaxy thermal conductivity transient thermoreflectance ultraviolet laser

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Phyllotaxis-inspired nanosieves with multiplexed orbital angular momentum

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eLight 2021年第1期1卷 46-56页

作者： Zhongwei Jin David Janoschka Junhong Deng Lin Ge Pascal Dreher Bettina Frank Guangwei Hu Jincheng Ni Yuanjie Yang Jing Li Changyuan Yu Dangyuan Lei Guixin Li Shumin Xiao Shengtao Mei Harald Giessen Frank Meyer zu Heringdorf Cheng-Wei Qiu Department of Electrical and Computer Engineering National University of Singapore4 Engineering Drive 3Singapore 117583Singapore College of Optical and Electronic Technology China Jiliang UniversityHangzhou 310018China Faculty of Physics and Center for Nanointegration Duisburg-Essen(CENIDE) University of Duisburg-EssenLotharstrasse 1-2147057 DuisburgGermany Department of Materials Science and Engineering Shenzhen Institute for Quantum Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China Beijing Qianjunyide Technology Co.Ltd Beijing 100031China. Physics Institute and Stuttgart Center of Photonics Engineering(SCoPE) University of Stuttgart70569 Stutt-gartGermany. School of Physics University of ElectronicScience and Technology of ChinaChengdu 611731China. Key Laboratory of Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China. Department of Electronic and Information Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARChina. Department of Materials Science and Engineering City University of Hong Kong83 Tat Chee AvenueKowloonHong Kong SARChina. State Key Laboratory On Tunable Laser Technology Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information SystemShenzhen Graduate SchoolHarbin Institute of TechnologyShenzhen 518055China.

Nanophotonic platforms such as metasurfaces,achieving arbitrary phase profiles within ultrathin thickness,emerge as miniaturized,ultracompact and kaleidoscopic optical vortex ***,it is often required to segment or interleave independent sub-array metasurfaces to multiplex optical vortices in a single nano-device,which in turn affects the device’s compactness and channel ***,inspired by phyllotaxis patterns in pine cones and sunflowers,we theoretically prove and experimentally report that multiple optical vortices can be produced in a single compact phyllotaxis nanosieve,both in free space and on a chip,where one meta-atom may contribute to many vortices *** time-resolved dynamics of on-chip interference wavefronts between multiple plasmonic vortices was revealed by ultrafast time-resolved photoemission electron *** nature-inspired optical vortex generator would facilitate various vortex-related optical applications,including structured wavefront shaping,free-space and plasmonic vortices,and high-capacity information metaphotonics.

关键词： Phyllotaxis vortex nanosieve Free-space Plasmonic vortices Ultrafast time-resolved

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