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Optimizing Lpbf-Parameters by Box-Behnken Design Allows to Print Crack-Free and Dense High-Boron Alloyed Stainless Steels

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SSRN 2024年

作者： Freitas, Brenda Juliet Martins Koga, Guilherme Yuuki Arneitz, Siegfried Bolfarini, Claudemiro de Traglia Amancio-Filho, Sergio Federal University of São Carlos Graduate Program in Materials Science and Engineering São Carlos13.565-905 Brazil Graz University of Technology Institute of Materials Science Joining and Forming Graz8010 Austria Federal University of São Carlos Department of Materials Engineering São Carlos13.565-905 Brazil Rod. Washington Luis São Carlos13565-905 Brazil

Boron has almost null solubility in iron, and its addition to stainless steels leads to the formation of hard borides, beneficial for increasing the wear resistance. However, these boron-containing steels have poor printability, with the occurrence of pronounced cracking, high porosity and risk of delamination. In this work Box-Behnken design coupled to analysis of variance (ANOVA) were used to optimize the LPBF (Laser Powder Bed Fusion) processing parameters of a highly boron-alloyed stainless steel reinforced with a boride network. The proposed models demonstrated to be accurate to determine the porosity percentage for the studied alloys, in which the laser power and scanning speed play the main role on the alloys’ densification, and absence of extensive defects. These results indicate that the use of design of experiments tools are essential to produce defect-free boron-modified stainless steel specimens with a relatively low number of experiments, identifying a narrow optimized processing window to build bulk composite materials. © 2024, The Authors. All rights reserved.

关键词： Design of experiments

Thickness, Annealing, and Surface Roughness Effect on Magnetic and Significant Properties of Co40Fe40B10Dy10 Thin Films

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materials 2023年第17期16卷 5995页

作者： Liu, Wen-Jen Chang, Yung-Huang Chiang, Chia-Chin Chen, Yuan-Tsung Wang, Yu-Zhi Wu, Chueh-Lin Lin, Shih-Hung Ou, Sin-Liang Department of Materials Science and Engineering I-Shou University Kaohsiung84001 Taiwan Bachelor Program in Industrial Technology National Yunlin University of Science and Technology 123 University Road Section 3 Douliou64002 Taiwan Department of Mechanical Engineering National Kaohsiung University of Science and Technology Kaohsiung80778 Taiwan Graduate School of Materials Science National Yunlin University of Science and Technology 123 University Road Section 3 Douliou64002 Taiwan Department of Electronic Engineering National Yunlin University of Science and Technology 123 University Road Section 3 Douliou64002 Taiwan Bachelor Program for Design and Materials for Medical Equipment and Devices Da-Yeh University Changhua51591 Taiwan

In this study, Co40Fe40B10Dy10 thin films were deposited using a direct current (DC) magnetron sputtering technique. The films were deposited on glass substrates with thicknesses of 10, 20, 30, 40, and 50 nm, and heat-treated in a vacuum annealing furnace at 100, 200, and 300 °C. Various instruments were used to examine and analyze the effects of roughness on the magnetic, adhesive, and mechanical properties. From the low frequency alternating current magnetic susceptibility (χac) results, the optimum resonance frequency is 50 Hz, and the maximum χac value tends to increase with the increase in the thicknesses and annealing temperatures. The maximum χac value is 0.18 at a film thickness of 50 nm and an annealing temperature of 300 °C. From the four-point probe, it is found that the resistivity and sheet resistance values decrease with the increase in film deposition thicknesses and higher annealing temperatures. From the magnetic force microscopy (MFM), the stripe-like magnetic domain distribution is more obvious with the increase in annealing temperature. According to the contact angle data, at the same annealing temperature, the contact angle decreases as the thickness increases due to changes in surface morphology. The maximal surface energy value at 300 °C is 34.71 mJ/mm2. The transmittance decreases with increasing film thickness, while the absorption intensity is inversely proportional to the transmittance, implying that the thickness effect suppresses the photon signal. Smoother roughness has less domain pinning, more carrier conductivity, and less light scattering, resulting in superior magnetic, electrical, adhesive, and optical performance. © 2023 by the authors.

关键词： Thin films

Ultrafine-Grained Stainless Steel with Wear-Resistant Nanoborides Decorating Grain Boundaries Produced by Laser Powder Bed Fusion

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SSRN 2024年

作者： Martins Freitas, Brenda Juliet Koga, Guilherme Yuuki Miguel Rodrigues, Luana Cristina Botta Filho, Walter José Amancio-Filho, Sergio de Traglia Bolfarini, Claudemiro Federal University of São Carlos Graduate Program in Materials Science and Engineering São Carlos13.565-905 Brazil Graz University of Technology Institute of Materials Science Joining and Forming Graz8010 Austria Federal University of São Carlos Department of Materials Engineering São Carlos13.565-905 Brazil Rod. Washington Luis São Carlos13565-905 Brazil

Stainless steel composites combine corrosion resistance and toughness of the metallic matrix with wear resistance granted by hard reinforcing nanoparticles. Given their near-net-shape manufacturing characteristics, additive manufacturing techniques are attractive to produce these hard and wear-resistant classes of materials with low machinability. In this work, from a SAF 2205 duplex stainless steel with boron addition, laser powder bed fusion (LBPF) was employed to produce an ultrafine-grained (~1 µm), dense (porosity ~0.1%), and crack-free ferritic-induced matrix composite with Cr2B-nanoborides reinforcing the grain boundaries (GBs) without formation of Cr-depleted regions. The composite showed significant higher hardness (up to 456 HV0.5) and wear resistance (4.4 x 10-5 mm3 N-1m-1) in sliding condition compared to a hot-rolled (225 HV0.5 and 2.9 x 10-3 mm3 N-1m-1) and a LPBF-produced SAF 2205 (314 HV0.5 and 3.3 x 10-4 mm3 N-1m-1). © 2024, The Authors. All rights reserved.

关键词： Wear of materials

Chemical and Microstructural Evaluation of Coatings for Yttrium Hydride Adjacent materials

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Chemical and Microstructural Evaluation of Coatings for Yttr...

2024 Nuclear and Emerging Technologies for Space, NETS 2024

作者： Shivprasad, A.P. Kohnert, C.A. Torrez, M.A. Tegtmeier, E. Emberley, C. Luther, E.P. Trellue, H.R. Materials Science and Technology Los Alamos National Laboratory Los AlamosNM United States Program Project Interface Los Alamos National Laboratory Los AlamosNM United States Sigma Division Los Alamos National Laboratory Los AlamosNM United States Nuclear Engineering and Nonproliferation Los Alamos National Laboratory Los AlamosNM United States

ISBN: (纸本)9780894487989

Yttrium hydride moderators enable more compact reactor designs for space nuclear applications. However, the high reactivity of yttrium hydride warrants investigation into barrier coatings to prevent chemical reactions between the hydride moderator and an adjacent material. The thermodynamics of coating-hydride systems were evaluated, and chemical interactions were explored through sintering of candidate coating materials with yttrium hydride. Resultant phases, microstructure, and chemical analyses were performed to determine viability of candidate coating materials. © 2024 AMERICAN NUCLEAR SOCIETY. All rights reserved.

关键词： Moderators

Study on synthesis and structural characterization of ZnO-doped g-C3N4materials for treatment of ciprofloxacin antibiotic in water 7

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Study on synthesis and structural characterization of ZnO-do...

7th International Scientific Conference on Applying New Technology in Green Buildings, ATiGB 2022

作者： Ha, Tran Thi Viet Viet, Nguyen Minh Tri, Nguyen Le Minh VNU Vietnam Japan University Master's Program in Environmental Engineering Faculty of Advanced Technologies and Engineering Hanoi Viet Nam VNU University of Science Faculty of Chemistry VNU Key Laboratory of Advanced Material for Green Growth Hanoi Viet Nam Advanced Institute of Materials Science Ton Duc Thang University Laboratory of Advanced Materials Chemistry Faculty of Applied Sciences Ho Chi Minh city Viet Nam

ISBN: (数字)9781665472852

ISBN: (纸本)9781665472852

Recently, the overuse and misuse of antibiotics are key factors leading to many negative problems to human and environment. Therefore, the removal for the antibiotics is very necessary, and photocatalysis is a highly efficient and environmentally friendly treatment method. Graphite carbon nitride (\mathrm{g}-\mathrm{C}_{3}\mathrm{N}_{4}) is an organic semiconductor, researched to create a 'new-generation' photocatalytic material system by hybridization with semiconductors such as TiO2 and ZnO, which offers potential energy in the decomposition of organic compounds using the energy of visible light. In this study, ZnO/g-C3N4 materials were synthesized and characterized by advanced techniques, then apply for ciprofloxacin antibiotic (CIP) treatment. The CIP degradation efficiency of the material reached 84.36% and after three times the material was regenerated, ZnO/g-C3N4 composite still showed excellent degradation ability. Therefore, ZnO/g-C3N4 materials can be applied in environmental remediation and many other fields. © 2022 IEEE.

关键词： Antibiotics

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

Multi-Scale Characterization of Supersaturated and Intermetallic Nanoscale Phases in an Al-Mg Alloy Produced by High-Pressure Torsion

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SSRN 2024年

作者： Wu, Yun-Hsuan Bhatta, Laxman Lee, Isshu Figueiredo, Roberto B. Kawasaki, Megumi Santala, Melissa K. Materials Science Program Oregon State University CorvallisOR97331 United States School of Mechanical Industrial and Manufacturing Engineering Oregon State University CorvallisOR97331 United States Department of Metallurgical and Materials Engineering Universidade Federal de Minas Gerais MG Belo Horizonte31270-901 Brazil

Nanostructured Al-Mg alloy was produced from disks of Mg sandwiched between Al through 100 turns of high-pressure torsion (HPT) at 6.0 GPa at room temperature, resulting in high microhardness of Hv 300–350 in regions experiencing a nominal shear strain greater than ~3500. While compositional mapping using scanning electron microscopy energy dispersive spectroscopy (EDS) showed a uniform distribution of Mg through the disk thickness at 1.5 and 3.0 mm from the disk center, transmission electron microscopy EDS showed a heterogeneous distribution of Mg remained on the nanoscale. Although HPT induces enough mixing to result in face-center-cubic Al with supersaturations of Mg of up to »20 at% near the disk surfaces, β-Al3Mg2, γ-Al12Mg17 and Al2Mg intermetallic phases were identified by electron diffraction throughout the disk thickness in regions experiencing high shear strain. This study captures detailed compositional heterogeneity throughout the sample thickness following intense mechanical alloying, nanoscale re-structuring, and phase transformations. © 2024, The Authors. All rights reserved.

关键词： Magnesium alloys

Optical Imaging of Flavor Order in Flat Band Graphene

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arXiv

arXiv 2024年

作者： Xie, Tian Wolf, Tobias M. Xu, Siyuan Cui, Zhiyuan Xiong, Richen Ou, Yunbo Hays, Patrick Holleis, Ludwig F. Guo, Yi Sheekey, Owen I. Patterson, Caitlin Arp, Trevor Watanabe, Kenji Taniguchi, Takashi Tongay, Seth Ariel Young, Andrea F. MacDonald, Allan H. Jin, Chenhao Department of Physics University of California at Santa Barbara Santa BarbaraCA93116 United States Department of Physics University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program School of Engineering for Matter Transport and Energy Arizona State University TempeAZ85287 United States Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan

Spin- and valley flavor polarization plays a central role in the many-body physics of flat band graphene1–21, with fermi surface reconstructions—often accompanied by quantized anomalous Hall1–8 and superconducting state9–14—observed in a variety of experimental systems. Here we describe an optical technique that sensitively and selectively detects flavor textures via the exciton response of a proximal transition metal dichalcogenide layer. Through a systematic study of rhombohedral and rotationally faulted graphene bilayers and trilayers, we show that when the semiconducting dichalcogenide is in direct contact with the graphene, the exciton response is most sensitive to the large momentum rearrangement of the Fermi surface, providing information that is distinct from and complementary to electrical compressibility measurements. The wide-field imaging capability of optical probes allows us to obtain spatial maps of flavor orders with high throughput, and with broad temperature and device compatibility. Our work paves the way for optical probing and imaging of flavor orders in flat band graphene systems. Copyright © 2024, The Authors. All rights reserved.

关键词： Graphene

Thermal Performance and Economic Evaluation of a Small Office Integrated with Phase Change materials

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SSRN 2023年

作者： Storm, Rafael Rank de Souza Barnasky, Ricardo Ritter Higa, Márcio de Oliveira, Júlio César Dainezi Maringá State University Colombo Avenue 5790 Maringá87020-900 Brazil Doctorate Program in Materials Science and Engineering Santa Catarina State University Brazil

The Phase Change materials (PCM) are one of the options to decrease the energy demand on edifications to meet the global climate challenges. These materials are characterized by a high value of latent heat, therefore increasing the building’s overall thermal inertia and decreasing the energy demand for thermal acclimatization. This paper studied the influence of theoretical layers of PCM in a typical commercial building located in different climate zones and performed an economic viability study for large scale applications Due to its unique characteristics, eight different Brazilian cities were chosen, in order to cover eight different bioclimates and three different PCM thickness were evaluated. Numerical simulations were performed in EnergyPlus with a standard edification developed by the U.S Department of Energy with changes in the building envelope in order to adapt the model to typical Brazilian envelopes. Phase change materials with twelve different phase change temperatures, varying from 25°C to 36°C, were compared to the reference scenario, in order to determine the most suitable temperature for each of the eight locations. Economic analyzes were performed based on the common prices of electricity and labor costs. The results showed a dynamic payback time between 27,3 and 43,3 years. © 2023, The Authors. All rights reserved.

关键词： Economic analysis