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Evidence for Two-Stage Hardening in an Al-Zn-Mg-Cu Alloy Processed by High-Pressure Torsion

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SSRN

SSRN 2022年

作者： dos Santos, Igor Cuzzuol Mazzer, Eric M. Figueiredo, Roberto B. Langdon, Terence G. Rodrigues Pereira, Pedro Henrique Graduate Program in Metallurgical Materials and Mining Engineering Universidade Federal de Minas Gerais MG Belo Horizonte31270-901 Brazil Department of Materials Science and Engineering Universidade Federal de São Carlos SP São Carlos13565-905 Brazil Department of Metallurgical and Materials Engineering Universidade Federal de Minas Gerais MG Belo Horizonte31270-901 Brazil Materials Research Group Department of Mechanical Engineering University of Southampton SouthamptonSO17 1BJ United Kingdom

Experiments were conducted to assess the effect of torsional straining on the microstructural evolution of an Al-5.7Zn-1.8Mg-2.1Cu alloy containing dispersed second phase particles prior to deformation. The results show that the material exhibits two distinct and consecutive hardening stages when processed through 1/8, 1, 5, 30, 50 and 100 turns in high-pressure torsion (HPT). There is an initial increase in the Vickers hardness from ~120 Hv in the unprocessed state to ~240 Hv after 1 turn. In this first stage, hardening occurs primarily through the accumulation and rearrangement of dislocations into fine cells/subgrains. A quasi-stationary condition is achieved with further straining where the microhardness remains nearly constant and the grain size is ~140 nm up to 30 revolutions. Thereafter, the microstructure consists of ultrafine and slightly elongated grains but the second phases are continuously fragmented. This fragmentation produces a new hardening stage and the development of a uniform array of highly elongated grains with an average size of ~93 nm after 100 HPT turns. It is shown that this two-stage hardening is consistent with conventional Hall-Petch strengthening and the development of the second stage is attributed to a reduction in grain boundary mobility due to the segregation of solutes. © 2022, The Authors. All rights reserved.

关键词： Aluminum alloys

An Investigation of Cu/Ni/Ga Interfacial Reaction with Different Ni/Ga Ratio

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An Investigation of Cu/Ni/Ga Interfacial Reaction with Diffe...

International Conference on Electronics Packaging (ICEP)

作者： Tzu-hsuan Huang Jian-wei Huang Zhih-feng Lin Shih-kang Lin Program on Semiconductor Packaging and Testing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan Taiwan Department of Materials Science and Engineering National Cheng Kung University Tainan Taiwan Hierarchical Green-Energy Materials (Hi-GEM) Research Center National Cheng Kung University Tainan Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan Taiwan

ISBN: (数字)9784991191176

ISBN: (纸本)9798350385908

In this article, we utilized electroplating method forming Cu/Ni/Ga structure. Interfacial reaction was investigated with different ratio of Ni: Ga 7:3 and 1:20. The result showed that Ga reacted with the substrates immediately as plated forming NiGas and CuGa2 compound respectively in different ratio of Ni: Ga. IMCs transformed into Ni 2 Ga 3 and Cu 31.3 Ga 16.3 respectively after 300°C heat treatment. This research explored a new optimizing idea in developing Ga TLP bonding technology.

关键词： Electrochemical deposition Gallium Heat treatment Plating Nickel Compounds Bonding

Mathematical modelling and optimization of parameters for Al-Si-Fe aluminum alloy reinforced by Al 2 O 3 and graphite particles using Taguchi method

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materials Today: Proceedings 2021年 44卷 979-986页

作者： Robale Dinsa Daba Devendra Kumar Sinha Habtamu Beri Satyam Shivam Gautam Gulam Mohammed Sayeed Ahmed Ram Sewak Singh Program of Mechanical Design and Manufacturing Engineering School of Mechanical Chemical and Materials Engineering ASTU ADAMA Ethiopia Department of Mechanical Engineering North Eastern Regional Institute of Science and Technology Itanagar India Department of Electronics and Communication School of Electrical Engineering and Computing ASTU ADAMA Ethiopia

In the present scenario the aluminum and its alloys are preferred due to requirement of lightweight high strength material. The present research article interrogates experimentally the study of actual density and porosity using powder metallurgy method. The experimental design is done using Taguchi L 16 orthogonal array. Actual density and porosity has been analyzed based on ‘smaller is best’ basis. Actual density and porosity are calculated using Archimedes principle. The leverage of four levels and five process parameters such as weight percentage of Al 2 O 3 , weight percentage of graphite, compaction pressure, compaction time and milling time are considered. Results reveal that Al 2 O 3 weight percentage has the highest leverage on density followed by compaction time and graphite weight percentage.

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Spectral analysis of high-order harmonic generation in carbon plasma using linearly, radially, and azimuthally polarized femtosecond pulses

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Optik 2024年 318卷

作者： Ganeev, R.A. Boltaev, G.S. Alnaser, A.S. Materials Research Center College of Arts and Science American University of Sharjah Sharjah26666 United Arab Emirates Department of Sciences Western Caspian University Istiglaliyyat Street 31 BakuAZ1001 Azerbaijan Department of Optics and Spectroscopy Voronezh State University Voronezh394006 Russia Department of Physics College of Arts and Sciences American University of Sharjah Sharjah26666 United Arab Emirates Materials Science and Engineering Program College of Arts and Sciences American University of Sharjah Sharjah26666 United Arab Emirates Department of Optics and Spectroscopy Voronezh State University Voronezh394018 Russia

We demonstrate high-order harmonic generation in carbon plasma using linearly, radially, and azimuthally polarized beams from a femtosecond laser (1030 nm, 40 fs, 50 kHz). The conditions for carbon plasma formation during laser ablation were optimized by adjusting the heating pulse energy in the cases of the single-color (1030 nm) and two-color (1030 nm + 515 nm) pump schemes to generate harmonics up to the 39th order. The application of radial and azimuthally polarized annular single-color (1030 nm) beams at optimal conditions of plasma formation allowed the demonstration of the spectral division and inclination of the vector harmonics. An asymmetric distribution of harmonics was obtained using the vortex beam generated during the propagation of laser radiation through the quarter-wave plate and S-waveplate. © 2024 Elsevier GmbH

关键词： Femtosecond lasers

Full Crystallographic Imaging of Hexagonal Boron Nitride Monolayers with Phonon-Enhanced Sum-Frequency Microscopy

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arXiv 2025年

作者： Mueller, Niclas S. Fellows, Alexander P. John, Ben Naclerio, Andrew E. Carbogno, Christian Gharagozloo-Hubmann, Katayoun Baláž, Damián Kowalski, Ryan A. Heenen, Hendrik H. Scheurer, Christoph Reuter, Karsten Caldwell, Joshua D. Wolf, Martin Kidambi, Piran R. Thämer, Martin Paarmann, Alexander Department of Physical Chemistry Fritz-Haber-Institute of the Max-Planck-Society Berlin14195 Germany Department of Chemical and Biomolecular Engineering Vanderbilt University NashvilleTN37235 United States Theory Department Fritz-Haber-Institute of the Max-Planck-Society Berlin14195 Germany Department of Physics Freie Universität Berlin Berlin14195 Germany Department of Mechanical Engineering Vanderbilt University NashvilleTN37235 United States Interdisciplinary Materials Science Program Vanderbilt University NashvilleTN37235 United States

Hexagonal boron nitride (hBN) is an important 2D material for van der Waals heterostructures, single photon emitters, and infrared nanophotonics. The optical characterization of mono- and few-layer samples of hBN however remains a challenge as the material is almost invisible optically. Here we introduce phase-resolved sum-frequency microscopy as a technique for imaging monolayers of hBN grown by chemical vapor deposition (CVD) and visualize their crystal orientation. A combination of femtosecond mid-infrared (IR) and visible laser pulses is used for sum-frequency generation (SFG), which is imaged in a wide-field optical microscope. The IR laser resonantly excites a phonon of hBN that leads to an ~800-fold enhancement of the SFG intensity, making it possible to image large 100x100 µm2 sample areas in less than 1 s. Implementing heterodyne detection in combination with azimuthal rotation of the sample further provides full crystallographic information. Through combined knowledge of topography and crystal orientation, we find that triangular domains of CVD-grown monolayer hBN have nitrogen-terminated zigzag edges. Overall, SFG microscopy can be used as an ultra-sensitive tool to image crystal structure, strain, stacking sequences, and twist angles, and is applicable to the wide range of van der Waals structures, where location and identification of monolayer regions and interfaces with broken inversion symmetry is of paramount importance. © 2025, CC BY.

关键词： Van der Waals forces

Generic synthesis of high-entropy phosphides for fast and stable Li-ion storage

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Energy and Environmental science 2024年第15期17卷 5387-5398页

作者： Li, Wenwu Li, Yanhong Wang, Jeng-Han Huang, Shengchi Chen, Anjie Yang, Lufeng Chen, Jie He, Lunhua Pang, Wei Kong Thomsen, Lar Cowie, Bruce Xiong, Peixun Zhou, Yucun Jang, Gun Min, Dong Hyun Byun, Jin Suk Xu, Lei Huang, Jia-Qi Roh, Kwang Chul Kang, Seo Hui Liu, Meilin Duan, Xiangfeng Park, Ho Seok School of Chemical Engineering Sungkyunkwan University 2066 Seoburo Jangan-gu Suwon440-746 Korea Republic of Department of Chemistry National Taiwan Normal University Taipei11677 Taiwan Department of Chemistry and Biochemistry University of California Los AngelesCA90095 United States School of Materials Science & Engineering Georgia Institute of Technology AtlantaGA30332 United States Institute of High Energy Physics Chinese Academy of Sciences Beijing China Spallation Neutron Source Science Center Dongguan China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China Institute for Superconducting & Electronic Materials University of Wollongong WollongongNSW Australia Australian Synchrotron Australian Nuclear Science and Technology Organization ClaytonVIC3168 Australia School of Materials Science and Engineering Beijing Institute of Technology Beijing100081 China Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing100081 China Energy Storage Materials Center Korea Institute of Ceramic Engineering and Technology Gyeongsangnam-do Jinju-Si52851 Korea Republic of Department of Materials Science and Engineering Korea University Anam-Dong Seongbuk-Gu Seoul136-713 Korea Republic of Sungkyunkwan University 2066 Seoburo Jangan-gu Suwon440-746 Korea Republic of Sungkyunkwan University 2066 Seoburo Jangan-gu Suwon440-746 Korea Republic of Sungkyunkwan University 2066 Seoburo Jangan-gu Suwon440-746 Korea Republic of

Monophosphides and bi-metallic phosphides have attracted considerable interest for their high-capacity Li-storage capacity, but are currently plagued by the sluggish charge transfer kinetics and large volume changes that hinder their practical applications. Herein, we design a triple-disordered-cation phosphide of GaGeSiP3 that combines the benefits of the high capacity of Si, high reactivity of P, fast Li ion conduction of Ge, and the self-healing capability of liquid metallic Ga. The GaGeSiP3 multinary compound features high configurational entropy, with excellent electronic conductivity, rapid Li-ion diffusion, and better resistance to volume change compared to the parent phases of GaGe2P3, GaSi2P3, Ge, and Si. Crystallographic and spectrographic analyses, electrochemical characterization and theoretical simulations confirm that GaGeSiP3 undergoes a reversible lithium storage mechanism based on a combination of intercalation and conversion reactions. The GaGeSiP3 anode delivers a high specific capacity of 1667 mA h g−1 with an initial coulombic efficiency of 90.3% and a low average operating potential of 0.47 V. Moreover, we further create graphite-modified GaGeSiP3 that combines intercalation and conversion storage to deliver a high rate capacity of 949 mA h g−1 at 20.0 mA cm−2, and an exceptional cycling stability to retain a capacity of 1121 mA h g−1 after 2000 cycles at 6.0 mA cm−2. Inspired by this unique feature of high structural entropy, we further synthesized quaternary mixed-cation ZnGaGeSiP4, CuGaGeSiP4, and AlGaGeSiP4;quinary mixed-cation ZnCuGaGeSiP5, ZnAlGaGeSiP5, and CuAlGaGeSiP5;and hexanary mixed-cation ZnCuAlGaGeSiP6, where the crystalline size was reduced due to the enhanced structural entropy. This work opens up a new synthesis paradigm, which overcomes the thermodynamic immiscibility among different metals and non-metals, for creating an attractive family of high-entropy multinary mixed-cation phosphides as advanced energy storage materials.

关键词： Charge transfer

Thermal Conductivity Measurement Using Modulated Photothermal Radiometry for Nitrate and Chloride Molten Salts

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arXiv 2023年

作者： Chung, Ka Man Feng, Tianshi Zeng, Jian Adapa, Sarath Reddy Zhang, Xintong Zhao, Andrew Z. Zhang, Ye Li, Peiwen Zhao, Youyang Garay, Javier E. Chen, Renkun Program in Materials Science and Engineering University of California San Diego La Jolla CA92093 United States Department of Mechanical and Aerospace Engineering University of California San Diego La Jolla CA92093 United States Department of Aerospace and Mechanical Engineering The University of Arizona TucsonAZ85721 United States National Renewable Energy Laboratory 15013 Denver West Parkway GoldenCO80401 United States

Molten salts are being used or explored for thermal energy storage and conversion systems in concentrating solar power and nuclear power plants. Thermal conductivity of molten salts is an important thermophysical property dictating the performance and cost of these systems, but its accurate measurement has been challenging, as evidenced by wide scattering of existing data in literature. The corrosive and conducting nature of these fluids also leads to time consuming sample preparation processes of many contact-based measurements. Here, we report the measurement of thermal conductivity of molten salts using a modulated photothermal radiometry (MPR) technique, which is a laser-based, non-contact, frequency-domain method adopted for molten salts for the first time. By unitizing the advantages of front side sensing of frequency-domain measurements and the vertical holder orientation, the technique can minimize the natural convection and salt creeping effects, thus yielding accurate molten salt thermal conductivity. The MPR technique is first calibrated using standard molten materials including paraffin wax and sulfur. It is then applied on measuring pure nitrate salts (NaNO3 and KNO3), solar salt (NaNO3–KNO3 mixture), and chloride salt (NaCl–KCl–MgCl2). The measurement results are compared with data from literature, especially those obtained from laser flash analysis (LFA). Our results demonstrate that the MPR is a convenient and reliable technique of measuring thermal conductivity of molten salts. Accurate thermal conductivity data of molten salts will be valuable in developing the next-generation high-temperature thermal energy storage and conversion systems. © 2023, CC BY.

关键词： Sodium nitrate

Superionic surface Li-ion transport in carbonaceous materials

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arXiv 2024年

作者： Zhou, Jianbin Wang, Shen Wu, Chaoshan Qi, Ji Wan, Hongli Lai, Shen Feng, Shijie Ko, Tsz Wai Liang, Zhaohui Zhou, Ke Harpak, Nimrod Solan, Nick Liu, Mengchen Hui, Zeyu Ai, Paulina J. Griffith, Kent Wang, Chunsheng Ong, Shyue Ping Yao, Yan Liu, Ping Department of Nanoengineering University of California San Diego La Jolla CA United States Materials Science and Engineering Program Texas Center for Superconductivity The University of Houston University of Houston HoustonTX United States Department of Chemical and Biomolecular Engineering University of Maryland College ParkMD United States Department of Chemistry and Biochemistry University of California San Diego La Jolla CA92093 United States The Bishop's School La Jolla CA92037 United States

Unlike Li-ion transport in the bulk of carbonaceous materials, little is known about Li-ion diffusion on their surface. In this study, we have discovered an ultra-fast Li-ion transport phenomenon on the surface of carbonaceous materials, particularly when they have limited Li insertion capacity along with a high surface area. This is exemplified by a carbon black, Ketjen Black (KB). An ionic conductivity of 18.1 mS cm-1 at room temperature is observed, far exceeding most solid-state ion conductors. Theoretical calculations reveal a low diffusion barrier for the surface Li species. The species is also identified as Li*, which features a partial positive charge. As a result, lithiated KB functions effectively as an interlayer between Li and solid-state electrolytes (SSE) to mitigate dendrite growth and cell shorting. This function is found to be electrolyte agnostic, effective for both sulfide and halide SSEs. Further, lithiated KB can act as a high-performance mixed ion/electron conductor that is thermodynamically stable at potentials near Li metal. A graphite anode mixed with KB instead of a solid electrolyte demonstrates full utilization with a capacity retention of ~85% over 300 cycles. The discovery of this surface-mediated ultra-fast Li-ion transport mechanism provides new directions for the design of solid-state ion conductors and solid-state batteries. Copyright © 2024, The Authors. All rights reserved.

关键词： Solid electrolytes

Efficient thermo-optic micro-ring phase shifter made of PECVD silicon-rich amorphous silicon carbide

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arXiv 2022年

作者： Chang, Li-Yang Sunny Pappert, Steve Yu, Paul K.L. Materials Science and Engineering Program The Department of Mechanical and Aerospace Engineering University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States Department of Electrical & Computer Engineering University of California San Diego 9500 Gilman Drive La Jolla CA92093 United States

In this work, the thermo-optic coefficient (TOC) of the silicon-rich amorphous silicon carbide (a-SiC) thin film deposited by plasma-enhanced chemical vapor deposition is characterized. We found that the TOC of the film increases as its silicon content increases. A more than three-fold improvement in the TOC is measured, reaching a TOC as high as 1.88 × 10−4 ℃−1, which is comparable to that of crystalline silicon. An efficient thermo-optic phase shifter has also been demonstrated by integrating the silicon-rich a-SiC micro-ring structure with a NiCr heater. Its tuning efficiency Pπ as low as 4.4 mW has been measured at an optical wavelength of 1550 nm. These findings make silicon-rich a-SiC a good material candidate for thermo-optic applications in photonic integrated circuits. Copyright © 2022, The Authors. All rights reserved.

关键词： Silicon carbide