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Microstructures and strengthening mechanism of oxygen soluted titanium by selective laser melting

Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy 2021年第2期68卷 67-75页

作者： Ichikawa, Eri Shitara, Kazuki Umeda, Junko Li, Shufeng Chen, Biao Kondoh, Katsuyoshi Dept. Mechanical Engineering School of Engineering Osaka University 2-1 Yamadaoka Suita565-0871 Japan Joining and Welding Research Institute Osaka University 11-1 Mihogaoka Ibaraki567-0047 Japan School of Materials Science and Engineering Xi'an University of Technology Xi'an710048 China State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an710072 China

The mechanical properties of selective laser melting (SLM) titanium (Ti) materials can be enhanced by solid solution with oxygen (O) element. However, the microstructure changes and their relationship with mechanical properties of SLM Ti materials have not been clearly revealed in the view point of the dissolved oxygen amount. In this study, we investigated the effect of oxygen element on the microstructures and mechanical properties of SLM ?-Ti materials. Furthermore, the strengthening mechanism of SLM Ti materials was also investigated quantitatively. The SLM Ti material without additional oxygen consisted of coarse grains, whereas the SLM materials with 0.35 ~ 0.89 mass% O consisted of acicular ?-Ti grains. As the oxygen amount increased, tensile strength was increased while maintaining a high elongation at break. The tensile strength of the 0.89 mass% O material increased by 764 MPa compared to the material without additional oxygen. The strengthening mechanism of SLM Ti-O alloys was quantitatively clarified to be oxygen solid solution and grain refinement strengthening. © 2021 Journal of the Japan Society of Powder and Powder Metallurgy. All rights reserved.

关键词： Titanium alloys

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Predictions of Burst Pressure of Carbon/Natural Fiber and Hybrid Composite Pressure Vessels by Theoretical and Numerical Analysis

SSRN

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SSRN 2023年

作者： Islam, Md. Mafidul Hossain, Md. Foisal Rana, Muhammed Sohel Ferdous, Md. Shafiul Department of Materials Science and Engineering Khulna University of Engineering & Technology Khulna9203 Bangladesh Department of Electronics and Communication Engineering Khulna University of Engineering & Technology Khulna9203 Bangladesh Cenrtal Engineering Facilities Atomic Energy Research Establishment Ganakbari Savar Dhaka1349 Bangladesh Former Faculty Dept. of Mechanical Engineering Khulna University of Engineering & Technology Khulna9203 Bangladesh

In this study, finite element modeling was used to assess the stress and burst strength of a composite pressure vessel (CPV). The fiber type and its sequences were taken into account while developing the best CPV. The stress produced inside the CPV may cause damage to the vessel as well as loss of life and property. Therefore, it is critical to ensure that the stress produced in the CPV does not exceed the vessel material's maximum allowable stress value. The primary goal of this research is to investigate the stresses induced in composite pressure vessels and then examine the stress using three different solutions: von Mises, Tresca, and ASSY. The theoretical burst strength is first established, and then a numerical solution is developed using ABAQUS. In order to verify the accuracy of FEA, the outcomes of the theoretical technique and the finite element method are compared. © 2023, The Authors. All rights reserved.

关键词： ABAQUS

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Production of reduced iron from mill scale waste using tilting rotary furnace

Results in Materials

引用

Results in materials 2023年 19卷

作者： El-Shiekh, Hazem El-Fawakhry, Mohamed K. Mitwally, Mohamed E. Shash, Ahmed Y. Faculty of Engineering and Materials Science German University in Cairo Cairo Egypt Steel and Ferroalloys Dept. Central Metallurgical Research and Development Institute (CMRDI) Cairo Egypt Mechanical Design and Production Dept. Faculty of Engineering Cairo University Cairo Egypt

The production of steel in steel mills generates undesired scales of oxidized iron on the surface of the hot steel. Although several attempts have been made to transform mill scale into valuable products, the low porosity of the oxides and the presence of oil contamination have been the main limitations in pelletizing the scales. In our recent research, we were able to produce reduced iron in the form of spheres with a 93% metallization degree using only mill scale as a source of iron without the need for any agglomeration or cleaning steps. The main equipment used in the production process was a tilting rotary furnace. We also examined the relationship between fuel consumption and the metallization degree of the reduced iron, as well as the effect of furnace RPM on the cross-sectional diameter of the produced spheres. By adjusting the process parameters, we were able to produce spheroidal iron with a cross-sectional diameter ranging from 10 mm to 400 mm. This high-quality reduced iron can be directly used as a replacement for DRI or scrap in traditional steel production methods. © 2023 The Authors

关键词： Iron and steel Mill scale Reduced iron Rotary furnace Waste

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Solid state processing of the cantor derived alloy CoCrFeMnNi by oxide reduction

Results in Materials

引用

Results in materials 2022年 14卷

作者： Gianelle, Madison A. Clapp, Chase Kundu, Animesh Chan, Helen M. Dept. of Materials Science & Engineering Lehigh University Bethlehem PA United States Dept. Mechanical Engineering & Mechanics Lehigh University Bethlehem PA United States

In recent years, high entropy alloys (HEAs), also known has Multi-Principal Element Alloys (MPEAs) have emerged as a new and exciting class of materials. One of the first (and most widely studied) HEA compositions is that of the so-called Cantor alloy, the equimolar CoCrFeNiMn composition. This paper reports on the synthesis of an HEA containing the same metallic elements via reduction of a mixture of the corresponding oxides. High purity precursor powders of Co(OH)₂, Cr₂O₃, Fe₂O₃, MnO₂, and NiO were milled and mixed using standard ceramic processing methods. The green pellets were subjected to a series of isothermal reduction anneals in flowing 3% H₂–Ar (which is below the flammability limit), at temperatures ranging from 1000 to 1185 °C, with annealing times from 24 to 120 h. The microstructure and phase evolution of the samples were characterized using SEM, EDS analysis, and XRD. Reduction heat-treatment at 1185 °C resulted in samples developing a core-shell structure, with a dense outer metallic layer, and a core consisting of a mixture of metallic and ceramic phases. Using EPMA (electron microprobe analysis), the composition of the HEA shell was determined to be Co_0·25Cr_0·19Fe_0·25Ni_0·23Mn_0.08. The hardness of the HEA was measured using Vickers micro-indentation. Examination of the individual indentation sites showed a strong positive correlation between the hardness value and the volume fraction of second phase particles (MnCr₂O₄, Cr₂O₃) within the indented area. A comparison between two sub-groups of indentation sites showed an 43% increase in average hardness (211.1 HV versus 148 HV) that was associated with a higher volume fraction of second phase (10.9% versus 2.9%). Consistent with thermodynamic considerations, experiments revealed that when a sample consisting solely of MnO₂

关键词： Cantor Extractive metallurgy High Entropy Oxide reduction Solid state synthesis

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Strengthening Mechanism of Sub-Nano P-Containing Particles on the Pb-Sn Bronze Alloy

SSRN

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SSRN 2022年

作者： Xiaoyan, Ren Guowei, Zhang Hong, Xu School of Materials Science and Engineering North University of China Shanxi Taiyuan030051 China Dept. of Mechanical Engineering Taiyuan Institute of Technology Shanxi Taiyuan030008 China

Cu-Pb20-Sn5 alloy is taken as the main research object, and the particle size, microstructure, mechanical properties and friction of Pb particles in Cu-Pb20-Sn5-xP(x=0,0.05,0.1,0.3,0.5) alloy were investigated in detail. The influence of P element on the tribological performance, the strengthening mechanism and wear behavior of Cu-Pb20-Sn5 alloy were discussed under the action of P to obtain a new Pb-Sn bronze alloy with high-performance applying for bimetallic cylinder block. The results showed that the addition of P element has a significant effect on the microstructure of Cu-Pb20-Sn5 alloy. The α(Cu) phase in Cu-Pb20-Sn5 alloy transform from coarse columnar grains to fine equiaxed grains and Pb particles were obviously refined. With the increase of P content, the size of Pb particles gradually decreased, especially in P content of 0.5wt.%, the average size of Pb particles decreased from 36.3µm without P while the grain size decreases to 24.5µm when the addition of P is 0.5wt.%. The reason for grain refinement is the addition of the supercooling degree of α(Cu) nucleation, accelerates its solidification rate, and forms a fine dendrite *** Pb particles become smaller for which the dendrite network has become *** the same time，the tensile strength and hardness of the Pb-Sn bronze alloy increase,the elongation was increased first and then decreased. Compared with the alloy without adding P, the tensile strength enhanced by 65.12% and the hardness increased by 68.5% when the addition of P was 0.5wt.%. When the content of P was 0.1wt.%, the elongation of 17.8% was the largest, which improves by 24.8%. The main strengthen mechanism was that nano-scale Ni3P and Cu3P phases dispersed into the matrix, hindering the movement of dislocations during deformation. Additionally, the grain refinement also contributed to the improvement of mechanical properties of alloy. © 2022, The Authors. All rights reserved.

关键词： Bronze

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Tuning heterogeneous structure and enhancing tensile properties in a FeCoCrNiMnPx high-entropy alloys

引用

materials science and engineering: A 2025年 936卷

作者： Li, Zhanjiang Zhao, Xianrui Xu, Yulang Du, Xunbai Chen, Li Li, Deyin Zhang, Qiangyong Zuo, Dunwen Lu, Wenzhuang Dai, Pinqiang Tang, Qunhua School of Naval Architecture & Intelligent Manufacturing Jiangsu Maritime Institute Nanjing211170 China Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and Astronautics Nanjing211106 China College of Materials Science and Engineering Fujian University of Technology Fuzhou350118 China Dept. of Material Engineering Fuzhou University Zhicheng College Fuzhou350002 China School of Mechanical & Electrical Engineering Putian University Putian351100 China

The effects of phosphorus addition and annealing temperature on the microstructure and mechanical properties of equal atomic ratio FeCoCrNiMn high-entropy alloys (HEAs) were systematically studied. The phase composition, microstructure, hardness, and tensile properties were examined. The results demonstrate that the heterogeneous structure consists of residual deformed grains, partially recrystallized grains, and fully recrystallized grains, which can be effectively tuned by increasing the P content. Furthermore, the addition of P delayed the recrystallization of the HEAs because of the precipitation of metal phosphides, which hindered dislocation movement and annihilation. The incorporation of P in HEAs not only avoids embrittlement but also achieves excellent strength-ductility synergy. For cold-rolled and annealed HEAs, as the P content increases from 0 to 0.03 (molar ratio), the yield strength is enhanced from 392.31 MPa to 926.64 MPa, while the alloy retains a significant tensile ductility of approximately 10 %. Microstructural analysis indicated that the increase in the strength of the homogenized HEAs is primarily due to the strong solid-solution effect of the P atoms. Based on detailed microstructural analysis, it was found that the strengthening mechanism was mainly related to the heterogeneous deformation-induced hardening of the heterogeneous structure. This study demonstrates that although P is traditionally regarded as an embrittlement element in steel, the addition of an appropriate amount of P can enhance the strength-ductility synergy in HEAs. © 2025 Elsevier B.V.

关键词： Tensile strength

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Further Experimental Evidence of the Dead Matter Has Memory Conjecture in Capacitive Devices

arXiv

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arXiv 2022年

作者： Allagui, Anis Zhang, Di Elwakil, Ahmed Dept. of Sustainable and Renewable Energy Engineering University of Sharjah United Arab Emirates Dept. of Mechanical and Materials Engineering Florida International University MiamiFL33174 United States Dept. of Electrical Engineering and Computer Science Khalifa University United Arab Emirates Dept. of Electrical and Software Engineering University of Calgary Alberta Canada

This study provides new sets of experimental results supporting Westerlund's conjecture that Dead Matter Has Memory [1]. Memory effects in the dynamic response of electric double-layer capacitors (EDLCs) that integrate its prior history of stimulation and state have been experimentally observed and reported in a few recent studies. The different excitation signals used to quantify such effects in these studies aimed at charging a device to the same voltage value and the exact same accumulated charge level but in different manners. Having reached the same unique voltage-charge point, it was observed that different yet repeatable discharge patterns occur, proving the existence of memory. The aim of this work is to provide further experimental evidence of the inherent memory effect in EDLCs in response to time-varying stationary input excitations with different statistical properties. In particular, different sets of charging voltage waveforms composed of fixed dc values with superimposed uniformly-distributed random fluctuations of different amplitudes were created and used to charge the same EDLC device to a unique voltage-charge point. The duration of these signals was the same but with different values of variance around the mean value. We observed different time-charge responses depending on the extent of the noise level in these charging waveforms. This is interpreted and discussed in the context of inherent memory using fractional-order voltage-charge equations of non-ideal capacitors. © 2022, CC BY.

关键词： Supercapacitor

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Ti30Zr10Hf10Ni35Cu15 high-entropy shape memory alloy with tunable transformation temperature and elastocaloric performance by heat treatment

引用

materials Today Advances 2023年 20卷

作者： Chang, Yen-Ting Lee, Ming-Hao Chu, Ming-Wen Hsu, Yi-Ting Chen, Chih-Hsuan Dept. of Mechanical Engineering National Taiwan University Taipei106 Taiwan Center for Condensed Matter Sciences National Taiwan University Taipei106 Taiwan The Key Consortium of Electron Microscopy National Taiwan University Taipei106 Taiwan Dept. of Materials Science and Engineering National Taiwan University Taipei106 Taiwan

This work investigates the influence of heat treatments on a pseudo-binary Ti30Zr10Hf10Ni35Cu15 high-entropy shape memory alloy. Heat treatments on the alloy resulted in the formation of second phases and thus were able to adjust its transformation temperatures. This phenomenon results from the formation of H-phase and (Zr,Hf)7Cu10 phase during low-temperature and high-temperature aging, respectively. The superelasticity of solution-treated, 500 °C-aged and 700 °C-aged samples was tested under compression, and all samples exhibited nearly 5 % recoverable strain and 15 °C elastocaloric cooling capacity. Further cyclic compression tests confirmed their stability, with up to 75 % of the initial cooling capacity retained after 5000 compression cycles. Due to its high yield strength, the Ti30Zr10Hf10Ni35Cu15 high-entropy shape memory alloy showed great superelasticity and elastocaloric performance at various testing temperatures. Furthermore, with heat treatments, the austenitic transformation finishing temperature (Af) of the alloy was tunable to between −10 °C (furnace-cooled) and 60 °C (700 °C-aged) with promising functional performance. These features expand the application range of TiZrHfNiCu high-entropy shape memory alloys as potential superelastic and elastocaloric materials. © 2023 The Authors

关键词： Entropy

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Testing and Estimation Methods of Crack Growth Life for Alloy 617 under Strain-Controlled Creep-Fatigue Conditions Using Circular Sharp Notched Round Bar Specimen

Testing and Estimation Methods of Crack Growth Life for Allo...

引用

2021 ASTM International Symposium on Advances in Accelerated Testing and Predictive Methods in Creep, Fatigue, and Environmental Cracking

作者： Ozeki, Go Yokobori, Toshimitsu A. Tabuchi, Masaaki Hayakawa, Masao Nikbin, Kamran Advanced Comprehensive Research Organization Teikyo University 2-21-1 Kaga Itabashi-ku Tokyo173-0003 Japan National Institute for Materials Science 1-2-1 Sengen Ibaraki Tsukuba305-0047 Japan Dept. of Mechanical Engineering Imperial College London Exhibition Rd. South Kensington LondonSW7 2AZ United Kingdom

ISBN: (纸本)9780803177338

Strain-controlled creep-fatigue crack growth tests were conducted using a circular sharp notched round bar specimen (CNS) for a nickel (Ni) base alloy, Alloy 617, which is a candidate material for the next-generation advanced ultra-supercritical (A-USC) power plant. The reduction ratio of stress range Δσ (=σmax - σmin) was found to be a dominant factor for estimating crack initiation and growth lives under strain-controlled creep-fatigue conditions as compared with that of tensile peak stress σmax. Additionally, the direct current potential drop (DCPD) technique was adopted in this research for measuring the crack length. The developed equation that is applied for a CNS was used for converting the output voltage into crack length. With the use of these measurement methods, the crack length of a CNS was found to be well estimated under hightemperature strain-controlled conditions. From these results, fundamental knowledge was obtained concerning the method for estimating crack growth life using CNSs under strain-controlled creep-fatigue conditions and also concerning the criteria for crack initiation and growth lives. Furthermore, when experimental results for Alloy 617 obtained by this research were compared with previous results for high-chromium (Cr) steel, the proposed method using the reduction ratio of Δσ was found to be applicable for both cases. © 2023 by ASTM International.

关键词： Creep

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Low losses Er3+-doped flexible planar waveguide: Toward an all-glass flexible planar photonic system

引用

Ceramics International 2023年第24期49卷 41217-41221页

作者： Carlotto, Alice Tran, Thi Ngoc Lam Babiarczuk, Bartosz Bazzanella, Nicola Szczurek, Anna Varas, Stefano Krzak, Justyna Bursi, Oreste S. Zonta, Daniele Lukowiak, Anna Righini, Giancarlo C. Ferrari, Maurizio Pietralunga, Silvia M. Chiasera, Alessandro IFN-CNR CSMFO Lab. and FBK Photonics Unit Via alla Cascata 56/C TN Povo38123 Italy Dept. of Physics Politecnico di Milano P.zza L. da Vinci 32 Milan20133 Italy Dept. of Materials Technology Faculty of Applied Sciences Ho Chi Minh City University of Technology and Education Vo Van Ngan Str. 1 Thu Duc District Ho Chi Minh City720214 Viet Nam Dept. of Mechanics Materials and Biomedical Engineering Wroclaw University of Science and Technology Smoluchowskiego 25 Wroclaw50-370 Poland Department of Physics University of Trento Via Sommarive 14 TN Povo38123 Italy Dept. of Civil Environmental and Mechanical Engineering University of Trento via Mesiano 77 TN Povo38123 Italy Institute of Low Temperature and Structure Research PAS ul. Okólna 2 Wroclaw50422 Poland IFAC-CNR MiPLab Via Madonna del Piano 10 Sesto Fiorentino50019 Italy IFN-CNR P.zza Leonardo da Vinci 32 Milan20133 Italy

Thin films have a crucial role in integrated optics. The development of passive and active devices such as splitters, waveguides, multiplexers and optical amplifiers is by now established on rigid substrates. Therefore, an important further step to improve this kind of technologies and open the route to new applications is to extend these functionalities to mechanically flexible devices. One fundamental brick to obtain this features extension is the fabrication of low loss inorganic active planar waveguides on flexible glass substrate. Here, we present the preliminary results of a novel top-down fabrication of an active SiO2–HfO2:Er3+ all-glass flexible planar waveguide, via radio frequency sputtering. The waveguiding system, deposited on ultrathin flexible glass substrate, showed an attenuation coefficient lower than 0.2 dB/cm at 1.53 μm and exhibits emission in the NIR region. © 2023 Elsevier Ltd and Techna Group S.r.l.

关键词： Sputtering

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