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Evaluation of Solubilization Time in Uncontrolled Atmosphere on Grain Growth, Phase Transformation Temperatures, and Mechanical Properties in a CuAlBe SMA

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Metallurgical and materials Transactions A: Physical Metallurgy and materials science 2025年

作者： da Silva Franco, Luiz Henrique Caluête, Rafael Evaristo de Lima, Bruno Alessandro Silva Guedes de Oliveira, Danniel Ferreira Brito, Ieverton Caiandre Andrade Department of Materials Engineering Federal University of Paraíba PB João Pessoa58051-900 Brazil Department of Mechanical Engineering Federal University of Paraíba PB João Pessoa58051-900 Brazil Graduate Program in Materials Science and Engineering Federal University of Paraíba PB João Pessoa58051-900 Brazil

Thermomechanical properties of SMAs are strongly affected by the metallurgical conditions imposed during their production. In this work, experiments were performed to investigate the behavior of the Cu–11.8Al–0.50Be (wt pct) SMA during solubilization at different times under an uncontrolled atmosphere. The results presented serve as a basis for predicting the macrostructure and thermomechanical properties in practical applications using CuAlBe SMAs. The grain growth evaluated by OM proved to be extremely sensitive to treatment time even after short intervals, tending to stabilize after 12 hours. Chemical analysis by EDS indicated a small variation in Al content produced during solidification, with 3 hours being enough to homogenize the Al concentration throughout the ingot despite producing a microstructure with non-uniform grain size. This variation in Al is not significant enough to influence the phase transformation temperatures, with the changes attributed to the grain growth and loss of Be by oxidation. ¼ hour resulted in the lowest values for maximum stress/strain, while 24 hours of solubilization showed the highest values of strain with small dispersion. The mixed fracture type (brittle/ductile) observed by SEM in the ¼ hour samples supports the hypothesis that ¼ hour is insufficient to dissolve the phases formed during solidification. This effect is aggravated by the strong elastic anisotropy, which contributes to embrittlement during quenching. © The Minerals, Metals & materials Society and ASM International 2025.

关键词： Setting

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!D-architected gratings for polarization-sensitive, nature-inspired structural color

arXiv

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arXiv 2024年

作者： Ibarra Miranda, Moisés H. Osterberg, Lars W. Shah, Dev H. Regulagadda, Kartik Poulikakos, Lisa V. Department of Mechanical and Aerospace Engineering Program of Materials Science and Engineering University of California San Diego La Jolla CA United States Program of Materials Science and Engineering University of California San Diego La Jolla CA United States Department of Mechanical and Aerospace Engineering University of California San Diego La Jolla CA United States Laboratory for Multiphase Thermofluidics and Surface Nanoengineering Department of Mechanical Engineering University of California BerkeleyCA United States

Structural coloration, a color-generation mechanism often found in nature, arises from light-matter interactions such as diffraction, interference and scattering, with micro- and nanostructured elements. Herein, we systematically study anisotropic,:D-architected grating structures with polarization-tunable optical properties, inspired by the vivid blue of Morpho butterfly wings. Using two-photon lithography, we fabricate multilayered gratings, varying parameters such as height (through scanning speed and laser power), periodicity, and number of layers. In transmission, significant color transitions from blue to brown were identified when varying structural parameters and incident light polarization conditions (azimuthal angle and ellipticity). Based on thin film diffraction efficiency theory in the Raman-Nath regime, optical characterization results are analytically explained, evaluating the impact of each parameter variation. Overall, these findings contribute to technological implementations of polarization-sensitive,:D-architected gratings for structural color applications. Copyright © 2024, The Authors. All rights reserved.

关键词： Color

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Novel ruthenium-based catalysts with atomic dispersion for oxygen evolution reaction in water electrolysis

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materials Today Chemistry 2024年 35卷

作者： Liao, Kuo-Wei Chen, Hsueh-Yu Wei, Wen-Hui Chen, Guan-Cheng Yamanaka, Ichiro Liu, Bo-Tau Hong, Ting-Fu Chiang, Tai-Chin Huang, Hsin-Chih Wang, Chen-Hao Department of Materials Science and Engineering National Taiwan University of Science and Technology Taipei106335 Taiwan Department of Chemical Science and Engineering School of Materials and Chemical Technology Tokyo Institute of Technology Meguro-ku Tokyo152-8552 Japan Department of Chemical and Materials Engineering National Yunlin University of Science and Technology Yunlin640301 Taiwan Department of Materials Engineering National Pingtung University of Science and Technology Pingtung912301 Taiwan Global Development Engineering Program National Taiwan University of Science and Technology Taipei106335 Taiwan Advanced Manufacturing Research Center National Taiwan University of Science and Technology Taipei106335 Taiwan

This study introduces a method for fabricating ultra-high-performance catalysts designed for the oxygen evolution reaction (OER), employing a combination of ball-milling, autoclave heat treatment procedures, and a two-step heat treatment approach. This method produces catalysts characterized by an atomic dispersion of ruthenium on nitrogen-doped carbon sheets (Ru–O/N–C–NH3). The Ru–O/N–C–NH3 catalyst exhibits exceptional OER activity in alkaline conditions, achieving a mass activity of 16842 A g−1Ru at 1.52 V, and a minimal overpotential of 290 mV at a current density of 10 mA cm−2. Moreover, this catalyst demonstrates enduring stability, showing no significant decay after a 100-h stability test in anion exchange membrane water electrolysis (AEMWE), with a mass activity approximating 62000 A g−1PGM. This is nearly three orders of magnitude greater than the AEMWE that utilizes commercial IrO2 as an anode. The atomic dispersion and the Ru–O/N bonding of the catalyst are substantiated to contribute to the notable enhancement in OER activity. © 2023 Elsevier Ltd

关键词： Ruthenium

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Synthesis of poly(lactide-co-glycolide) containing high glycolide contents by ring-opening polymerization as well as their structural characterizations, thermal properties, morphologies, and hydrophilicity

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Journal of Applied Polymer science 2023年第3期140卷

作者： Phan, Van Hoang-Khang Tai, Yi-Hsin Chiang, Tai-Chin Yu, Chin-Yang Department of Materials Science and Engineering National Taiwan University of Science and Technology Taipei Taiwan Global Development Engineering Program National Taiwan University of Science and Technology Taipei Taiwan

Random copolymers, poly(l-lactide-r-glycolide) are synthesized by one-pot ring-opening polymerization of l-lactide and glycolide in the presence of stannous octoate and 1-dodecanol. Block copolymers, poly(l-lactide-b-glycolide) are synthesized by ring-opening polymerization of l-lactide to generate poly(l-lactide) first and then further ring-opening polymerization of glycolide in the presence of poly(l-lactide) and stannous octoate. The composition ratio of l-lactide and glycolide is determined by the integration of the corresponding signals from 1H NMR spectra, which is consistent with the feeding ratio. Very few hetero-sequences can be observed for block copolymers due to well-defined microstructures. The block copolymers are more thermally stable than that of the random copolymers. The degree of crystallinity of the bock copolymers is relatively high compared to that of the random copolymers. The image of the block copolymers determined by field-emission scanning electron microscopy (FESEM) shows partial aggregate domains containing spherical particles with an average diameter of around 200 nm, which is very different from that of the random copolymers. Block copolymers are more hydrophilic than that of the random copolymers due to the ordered structure and amphiphilic behavior of the block series. © 2022 Wiley Periodicals LLC.

关键词： Microstructure

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Ethylene Glycol-Manipulated Syntheses of Calcium Carbonate Particles and DNA Capsules toward Efficient ATP-Responsive Cargo Release

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ACS Applied Bio materials 2023年第8期6卷 3351-3360页

作者： Lin, Yu-Hsuan Singuru, Murali Mohana Rao Marpaung, David Septian Sumanto Liao, Wei-Ching Chuang, Min-Chieh Department of Chemistry Tunghai University Taichung407224 Taiwan International Ph.D. Program in Biomedical and Materials Science Tunghai University Taichung407224 Taiwan Department of Biosystems Engineering Institut Teknologi Sumatera Lampung Selatan35365 Indonesia Institute of Biochemistry and Molecular Biology National Yang Ming Chiao Tung University Taipei112304 Taiwan

Cargo molecule-encapsulated DNA capsules synthesized with a solid sacrificial template have elicited significant interest in the last decade and have been used for active materials in applications ranging from biosensors to drug delivery. However, the correlation between template properties and the subsequent assembly and triggered release behavior of the resultant carriers remain uninvestigated. In this study, ethylene glycol (EG) was added during the CaCO3 precipitation synthesis to yield particles of various sizes and surface properties, and the adenosine triphosphate (ATP)-responsive release characteristics of the fabricated DNA capsules affected by these particle properties were investigated. The geometry, crystallization, and surface morphology of the CaCO3 particles co-precipitated at various EG concentrations were characterized. We discuss the integrity of cross-linking hybridization, fluorescent molecule internalization, degree of leakage, and release efficiency of the resulting DNA capsules and their relevance brought by particle properties. To achieve efficient encapsulation and cargo release, the surface roughness of the CaCO3 particles was explored and was deemed a key determinant of the compactness of the DNA shell after template removal. This effect was particularly strong in CaCO3 particles in connection with high EG concentrations. The DNA capsules fabricated using 83% EG exhibited low leakage, high loading, and moderate release efficiencies as well as a greater apparent association constant with ATP due to their small particle size and the high-integrity DNA shells. © 2023 American Chemical Society.

关键词： Ethylene glycol

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EFFECT OF BALL MILLING ON THE MAGNETIC PERFORMANCE OF STRONTIUM FERRITE (SrFe12O19) POWDERS

EFFECT OF BALL MILLING ON THE MAGNETIC PERFORMANCE OF STRONT...

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SAMPE 2024 Conference and Exhibition

作者： Arigbabowo, Oluwasola K. Hassan, Mehadi Asadollahnejad, Azin Islam, Md Shafikul Price, Holt Geerts, Wilhelmus J. Tate, Jitendra Materials Science Engineering and Commercialization Program Texas State University 601 University Drive San MarcosTX78666 United States Ingram School of Engineering Texas State University 601 University Drive San MarcosTX78666 United States Department of Physics Texas State University 601 University Drive San MarcosTX78666 United States

ISBN: (纸本)9781934551455

The primary advantage of the high energy ball milling (HEBM) process is its ability to synthesize a homogeneous mixture with submicron (up to nanoscale) particle size. This approach is a viable process for particle size reduction and grain refinement of magnetic powders, which affects their domain structure and by extension the resulting magnetic properties. In this research, we designed a 9-ball milling experiment by keeping the rotational speed constant at 300rpm and varying the ball-to-powder ratio of 5:1, 8:1, and 10:1 for 6hrs, 10hrs, and 14hrs milling times. The strontium ferrite magnetic powders subjected to HEBM were analyzed for crystallite size and behavior via XRD, particle size reduction via SEM/ImageJ software/originLabPro, and magnetic performance via powder-based VSM measurement. The magnetic performance of the ball-milled strontium ferrite powders shows a good combination of appreciable increment in the S-values (a ratio of the remanence to saturation magnetization) and a considerable decline in coercivity ( © 2024 Soc. for the Advancement of Material and Process engineering. All rights reserved.

关键词： Grain refinement

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MAGNETIC PROPERTIES EVALUATION OF POLYAMIDE 4.6 BONDED MAGNETIC COMPOSITE

MAGNETIC PROPERTIES EVALUATION OF POLYAMIDE 4.6 BONDED MAGNE...

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SAMPE 2024 Conference and Exhibition

作者： Karkhanis, Pratik Arigbabowo, Oluwasola K. Gonzalez, Aaron J. Inamdar, Shreyas Ahmed, Tanvir Herrera, Andres Geerts, Wilhelmus J. Tate, Jitendra S. Ingram School of Engineering Texas State University 601 University Drive San MarcosTX78666 United States Materials Science Engineering and Commercialization Program Texas State University 601 University Drive San MarcosTX78666 United States Department of Physics Texas State University 601 University Drive San MarcosTX78666 United States

ISBN: (纸本)9781934551455

Bonded magnetic composites combine the cost-effectiveness, low density, and manufacturing flexibility of conventional polymer binders with the unique magnetic characteristics of magnetic powders/fillers to form multifunctional magneto polymeric composites that offer superior properties to conventional sintered magnets. In this study, a co-rotating twin screw extruder was used to fabricate 20 and 40 wt.% strontium ferrite/polyamide 4.6 bonded magnetic composites viable for fused filament fabrication 3D printing. The characterization conducted on the bonded magnetic composites was scanning electron microscopy, simultaneous differential thermogravimetry, and vibrating sample magnetometry. The microstructure of the bonded composite exhibited a uniform platelet morphology of the strontium ferrite magnetic particles. There was no observable depreciation in the melting transitions, which suggests a thermally resistant magnetic composite. An appreciable increment in % crystallinity of 13 and 20% for 20wt.% and 40wt.% strontium ferrites bonded magnets were observed. This is attributable to the heterogeneous nucleation phenomenon, where the metal powders act as nucleation sites for increased crystalline domains. The bonded composite exhibited significant magnetic anisotropy, with the remanence (Mr), which is the most important property for magnetic application significantly increasing to 49.8% along the easy direction in comparison to the hard axis. This suggests the viability of the fabricated bonded composites in viable in producing anisotropic bonded magnetic devices, which are considered to exhibit stronger magnetic properties. © 2024 Soc. for the Advancement of Material and Process engineering. All rights reserved.

关键词： Magnetic anisotropy

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Study on the Flow, Foaming Characteristics and Structural Strength of Polypropylene Structural Foam Injection Molding by Innovative Nitrogen and Molten Plastic Mixing Mechanism

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Polymers 2023年第9期15卷 2116-2116页

作者： Huang, Po-Wei Peng, Hsin-Shu Hwang, Sheng-Jye Huang, Chao-Tsai Program of Mechanical and Aeronautical Engineering Feng Chia University of Engineering and Science Taichung407102 Taiwan Department of Mechanical and Computer Aided Engineering Feng Chia University of Engineering and Science Taichung407102 Taiwan Department of Mechanical Engineering National Cheng Kung University of Engineering Tainan70101 Taiwan Department of Chemical and Materials Engineering Tamkang University of Engineering New Taipei City251301 Taiwan

Plastic foam molding methods include thermoforming, extrusion and injection molding. Injection foam molding is a one-time molding method with high production efficiency and good product quality. It is suitable for foamed plastic products with complex shapes and strict size requirements. It is also the main method for producing structural bubbles. In this investigation, we developed a structural foam injection molding technology using the gas supply equipment connected to the unique plasticizing mechanism of the injection machine and studied its influence on the specimens’ melt rheology quality and foam structures. In the experiment, the forming material was polypropylene (PP), and the gas for mixing/forming foaming characteristics was nitrogen (N2). Additionally, in order to observe the rheological properties of N2/melt mixing, a melt flow specimen mold cavity was designed and the change in the melt viscosity index was observed using a melt pressure sensing element installed at the nozzle position. With the nitrogen supply equipment connected to a unique plasticizing mechanism, the mixing of gas and molten plastic can be achieved at the screw plasticizing stage, where the foaming effect is realized during the melt-filling process due to the thermodynamic instability of the gas. It was also found that an increase in N2 fill content increased melt fluidity, and the trend of melt pressure and melt viscosity index showed that the higher the gas content, the lower the trend. The foaming characteristic depends on the gas thermodynamic instability and the pressure release, so it can be seen from the melt fill path that, the greater the pressure near the gate, the lower the foaming amount and the internal structure (SEM) after molding;the farther from the gate, the greater the relative increase in the foaming growth/amount. This phenomenon will be more obvious when the N2 fill content is increased. © 2023 by the authors.

关键词： Gases

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Dielectric properties of cr3+ doped al2o3 of a hierarchical nanostructure synthesized using a highly porous precursor of tubular alo(Oh)⋅αh2o fibers 2nd

Dielectric properties of cr3+ doped al2o3 of a hierarchical ...

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2nd International Conference on materials science and Manufacturing Technology, ICMSMT 2020

作者： Jangu, Surendra Sharma, Sanjeev Kumar Sudhansu, Amit Kumar Ram, Shanker Materials Science Centre Indian Institute of Technology Kharagpur West Bengal721302 India Department of Ceramic Engineering University College of Engineering and Technology Bikaner Rajasthan334004 India

ISBN: (纸本)9783035737530

Herein, we have developed a Cr3+ doped Al2O3 of a hierarchical nanostructure by a simple two-step synthesis. A pure AlO(OH)⋅αH2O, as synthesized in forms of small tubular fibers by hydrolysis of Al-metal sheets, is easily doped with selective Cr3+ dosages up to 2.0 mol% using an aqueous CrO3. As-synthesized samples exhibit XRD of a single-phase Cr3+: Al2O3 of a rhombohedral crystal structure. The average pore volume is decreased as 98.1, 89.8, and 61.5 cm3-g-1 in the 0.5, 1.0, and 2.0% Cr% doped samples, with an average pore radius of 1.70, 2.17, and 1.90 nm, respectively, as measure from BET specific surface area. Local Al-O vibrations exhibit IR bands of 400 to 1200 cm-1 intrinsic of oxygen polygons. At room temperature, a duly tailored dielectric permittivity of 480 is obtained in a 2.0 mol% Cr3+: Al2O3 and that is enhanced progressively on heating it over 25 to 300 °C, showing a value 6700 at 300°C in phonon induced dynamics of charge carriers, useful for solid-state electronics. © 2021 Trans Tech Publications Ltd, Switzerland.

关键词： Nanostructures

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Inductively coupled plasma etching of orthorhombic gallium oxide films grown by mist chemical vapor deposition

Inductively coupled plasma etching of orthorhombic gallium o...

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IEEE Photonics Conference (IPC)

作者： Yara Banda Seong-Ho Cho Yanqing Jia Si-Young Bae Tien Khee Ng Boon S. Ooi Photonics Laboratory King Abdullah University of Science and Technology Thuwal Saudi Arabia Semiconductor Materials Center Korea Institute of Ceramic Engineering and Technology Jinju Republic of Korea Department of Materials Science and Engineering Pusan National University Busan Republic of Korea

We developed an inductively coupled plasma etching process for orthorhombic phase gallium oxide films through tuning of process parameters. We achieved a high etch rate of 130 nm/min while showing a surface roughness ...

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