المؤلفون: Pengfei Shan, Yiwei Shi, Xingping Lai, Wei Li, T.Y. Yang, Chenwei Li, Piaoping Yang

مصطلحات موضوعية: Rock Mechanics and Engineering, Mechanics of Materials, Engineering, Physical Sciences, Coalbed Methane Recovery and Utilization Practices, Ocean Engineering, Applications of Ground-Penetrating Radar in Geoscience and Engineering, Coal Permeability, Coal, Deformation meteorology, Materials science, Infrared, Disturbance geology, Coal mining, Dynamic load testing, Rock mass classification, Structural engineering, Geotechnical engineering, Geology, FOS Earth and related environmental sciences, Environmental science, Composite material, Optics, Physics, Paleontology, Waste management

الوصف: Coal deformation and damage are the fundamental causes of mining disasters. This paper proposes an intelligent sensing method of infrared thermal imaging applied to the qualitative analysis of deformation and damage of coal mass during loading. A thermal infrared imager and crack monitoring equipment were used to jointly monitor the average infrared radiation temperature (AIRT) and damage pattern of coal samples under complex disturbances during uniaxial loading. The time-frequency characteristics of infrared radiation during the coal sample destruction process were analyzed; and a Mask R-CNN crack recognition model was constructed to detect different crack shapes after the coal sample was destroyed. The results show that the uniaxial compressive strength of coal samples under static load is greater than the combined disturbance of dynamic and static loads, the degree of deformation and damage of the coal sample is more severe, and the cracks are more obvious; the uniaxial compressive strength of ... : ملخص تشوه الفحم وأضراره هي الأسباب الأساسية لكوارث التعدين. تقترح هذه الورقة طريقة استشعار ذكية للتصوير الحراري بالأشعة تحت الحمراء يتم تطبيقها على التحليل النوعي لتشوه وتلف كتلة الفحم أثناء التحميل. تم استخدام جهاز تصوير بالأشعة تحت الحمراء الحرارية ومعدات مراقبة الشقوق للمراقبة المشتركة لمتوسط درجة حرارة الأشعة تحت الحمراء (AIRT) ونمط تلف عينات الفحم تحت الاضطرابات المعقدة أثناء التحميل أحادي المحور. تم تحليل خصائص التردد الزمني للأشعة تحت الحمراء أثناء عملية تدمير عينة الفحم ؛ وتم إنشاء نموذج التعرف على تشقق قناع R - CNN للكشف عن أشكال التشققات المختلفة بعد تدمير عينة الفحم. تظهر النتائج أن مقاومة الانضغاط أحادية المحور لعينات الفحم تحت الحمل الثابت أكبر من الاضطراب المشترك للأحمال الديناميكية والثابتة، ودرجة تشوه وتلف عينة الفحم أكثر شدة، والشقوق أكثر وضوحًا ؛ مقاومة الانضغاط أحادية المحور للأحمال الديناميكية والثابتة منخفضة التردد أعلى من اضطراب الأحمال الديناميكية والثابتة عالية التردد ؛ اقترح طريقة تحليل التوقيت الصيفي لعينات الفحم ومؤشر جديد لتلف عينة الفحم. يمكن أن توفر نتائج البحث مؤشرات مرجعية ...

العلاقة: https://dx.doi.org/10.60692/72tx1-bvb68Test

الإتاحة: https://doi.org/10.60692/8phw9-c5f6710.60692/72tx1-bvb68Test

المؤلفون: Cheng Guo, Dongchu Chen, Mikhail L. Zheludkevich, Wei Li, Lianxi Chen, Zhentao Yu, Xiaojian Wang, Junjie Yang, Carsten Blawert

المصدر: Chen, L.; Guo, C.; Blawert, C.; Yang, J.; Chen, D.; Wang, X.; Yu, Z.; Zheludkevich, M.; Li, W.: Evaluation of the biodegradation product layer on Mg-1Zn alloy during dynamical strain. In: Journal of Magnesium and Alloys. Vol. 9 (2021) 5, 1820-1833. (DOI: /10.1016/j.jma.2021.07.002)
Journal of Magnesium and Alloys, Vol 9, Iss 5, Pp 1820-1833 (2021)

مصطلحات موضوعية: Dynamic deformation, Mining engineering. Metallurgy, Materials science, Protein, Simulated body fluid, Alloy, TN1-997, technology, industry, and agriculture, Metals and Alloys, Impedance, engineering.material, Biodegradable Mg alloy, Corrosion, Dielectric spectroscopy, Mechanics of Materials, Degradation layer, Ultimate tensile strength, engineering, Surface layer, Composite material, Deformation (engineering), Layer (electronics)

الوصف: Magnesium (Mg) alloys are attractive biodegradable implant materials. The degradation products on Mg alloys play a critical role in the stability of the interface between implant and surrounding tissue. In the present study, the effects of dynamic deformation on the interface layer of biomedical Mg-1Zn alloy were investigated using the constant extension rate tensile tests (CERT) coupled with electrochemical impedance spectroscopy (EIS). The deformation of the Mg-1Zn alloy had an adverse influence on the impedance of the surface degradation layer formed in simulated body fluid that only containing inorganic compounds. However, the surface degradation layer with improved corrosion resistance was obtained for the strained samples tested in protein-containing simulated body fluid. The spontaneous or enhanced adsorption of protein into the degradation product led to a flexible and stable hybrid anti-corrosive layer. A relationship between the dynamic deformation of Mg alloy and the impendence of the degradation layer was established, which demonstrates the necessity for in situ characterisation of the evolution of the surface layer under dynamic condition.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e43e3e8331dc43ef4905d062e149283cTest
https://doi.org/10.1016/j.jma.2021.07.002Test

المؤلفون: Xu-wei Li

المصدر: Shock and Vibration, Vol 2019 (2019)

مصطلحات موضوعية: Article Subject, 0211 other engineering and technologies, 02 engineering and technology, engineering.material, 0203 mechanical engineering, Ultimate tensile strength, medicine, Interlocking, 021101 geological & geomatics engineering, Civil and Structural Engineering, Shearing (physics), business.industry, Embedment, Mechanical Engineering, Grout, Stiffness, Structural engineering, Test method, Geotechnical Engineering and Engineering Geology, Condensed Matter Physics, lcsh:QC1-999, 020303 mechanical engineering & transports, Mechanics of Materials, engineering, medicine.symptom, business, Failure mode and effects analysis, lcsh:Physics, Geology

الوصف: Cable bolts help surrounding rock masses of underground excavations to form internal rock structure and thus self-stabilize through effective load transfer between rock masses and cable bolts. The load transfer characteristics of cable bolt play the most significant role in cable selection for support design. There are many factors potentially affecting the load transfer characteristics of cable bolt via strengthening or weakening load contributors such as cable bonding, mechanical interlocking, frictional resistance at cable-grout interface and grout-rock interface, and shearing of grout anchorage. Double embedment pull test (DEPT) is an effective, reliable, and repeatable test method of investigating the load transfer characteristics of cable bolt and thus was selected in this study. With DEPT, the influence of factors such as cable rotation, grout age, grout anchorage annulus thickness, cable wire profile, and failure mode on the load transfer characteristics of cable bolt were investigated in terms of tensile strength and stiffness in different loading stages. Conclusions drawn from the study can be used to improve cable installation quality and to select appropriate cable bolting technique.

وصف الملف: text/xhtml

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::06786095659301000d2c21d4dc033699Test
https://doi.org/10.1155/2019/2106741Test

المؤلفون: Xun Sun, Song Lu, Xianghai An, Levente Vitos, Wei Li, Chuanxin Liang, Tianlong Zhang, Ruiwen Xie, Hualei Zhang, Xiangdong Ding, Yunzhi Wang

المصدر: Materials & Design, Vol 199, Iss, Pp 109396-(2021)

مصطلحات موضوعية: Work (thermodynamics), Materials science, Twinning, Alloy, Thermodynamics, FOS: Physical sciences, Stacking fault energy, 02 engineering and technology, Applied Physics (physics.app-ph), engineering.material, 010402 general chemistry, 01 natural sciences, Metastable alloy, Condensed Matter::Materials Science, Annan materialteknik, Stacking-fault energy, Phase (matter), Metallurgy and Metallic Materials, lcsh:TA401-492, General Materials Science, Other Materials Engineering, Astrophysics::Galaxy Astrophysics, Condensed Matter - Materials Science, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), Physics - Applied Physics, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Deformation mechanism, Mechanics of Materials, Martensitic transformation, engineering, Partial dislocations, Density functional theory, lcsh:Materials of engineering and construction. Mechanics of materials, Deformation (engineering), Metallurgi och metalliska material, 0210 nano-technology

الوصف: Stacking fault energy (SFE) plays an important role in deformation mechanisms and mechanical properties of face-centered cubic (fcc) metals and alloys. In many concentrated fcc alloys, the SFEs determined from density functional theory (DFT) calculations and experimental methods are found having opposite signs. Here, we show that the negative SFE by DFT reflects the thermodynamic instability of the fcc phase relative to the hexagonal close-packed one; while the experimentally determined SFEs are restricted to be positive by the models behind the indirect measurements. We argue that the common models underlying the experimental measurements of SFE fail in metastable alloys. In various concentrated solid solutions, we demonstrate that the SFEs obtained by DFT calculations correlate well with the primary deformation mechanisms observed experimentally, showing a better resolution than the experimentally measured SFEs. Furthermore, we believe that the negative SFE is important for understanding the abnormal behaviors of partial dislocations in metastable alloys under deformation. The present work advances the fundamental understanding of SFE and its relation to plastic deformations, and sheds light on future alloy design by physical metallurgy.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e853692f429f844630789ecf7544b0f0Test
http://www.sciencedirect.com/science/article/pii/S0264127520309321Test

المؤلفون: Lei Xu, Jinhui Peng, Wei Chenlong, Wei Li, Libo Zhang

المصدر: High Temperature Materials and Processes, Vol 38, Iss 2019, Pp 370-379 (2019)

مصطلحات موضوعية: Technology, Materials science, molten salt, chromium carbide coatings, microwave heating, Chemicals: Manufacture, use, etc, 02 engineering and technology, TP1-1185, engineering.material, 01 natural sciences, Microwave assisted, chemistry.chemical_compound, 81.05.uw, diamond, 0103 physical sciences, General Materials Science, Physical and Theoretical Chemistry, Molten salt, 61.66.fn, 010302 applied physics, Materials processing, Chemical technology, Diamond, TP200-248, 021001 nanoscience & nanotechnology, Condensed Matter Physics, chemistry, Chemical engineering, Mechanics of Materials, Microwave heating, engineering, 81.40. ± z, 0210 nano-technology, number, Chromium carbide

الوصف: Chromium carbide (Cr3C2) coatings on the diamond were fabricated using the mixtures of molten salt of NaCl and BaCl2, powders of metallic chromium and diamond as raw materials in the temperature range of 750–900 °C by the microwave-assisted molten-salt synthesis. The morphology, microstructure and phase composition of the surface layer were characterized by Scanning Electron Microscopy, Energy-dispersive Spectrometry and X-ray diffraction. The results show that the surface of the diamond particles could be coated with Cr, forming a uniform and continuous Cr3C2-coated layer. The coatings thickness on the diamond can be controlled by adjusting the heating temperature and time. The coating thickness expanded from 0.73 to 2.30 µm when the temperature was increased from 750 °C to 900 °C, and increasing rapidly during the temperature range of 800 °C–850 °C, the coating thickness expanded from 1.30 to 2.80 µm when the holding time was increased from 0.5 h to 4 h. The results illustrate that the microwave-assisted molten salt synthesis plays a positive role in chromium coatings on the diamond, offering a potent method for the surface metallization of diamond.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d2539788f6d737cc859c947caff7e61fTest
https://doaj.org/article/9e69492b83414fafb2c05c0243b30b96Test

المؤلفون: Xinying Wang, Yuqi Liu, Wei Li, Binfang Meng, Libo Zhang

المصدر: High Temperature Materials and Processes, Vol 36, Iss 8, Pp 779-787 (2017)

مصطلحات موضوعية: Technology, Materials science, Chemicals: Manufacture, use, etc, TP1-1185, Astrophysics::Cosmology and Extragalactic Astrophysics, 02 engineering and technology, oxidized ilmenite concentrate, engineering.material, 020501 mining & metallurgy, Condensed Matter::Materials Science, General Materials Science, microwave-absorbing characteristics, Physics::Chemical Physics, Physical and Theoretical Chemistry, 61.66.fn, xrd, Chemical technology, digestive, oral, and skin physiology, Metallurgy, TP200-248, Condensed Matter Physics, 0205 materials engineering, Mechanics of Materials, engineering, 81.40. ±z 81.05 ±t 81.40.wx, Microwave, Ilmenite

الوصف: Microwave-absorbing characteristics of the oxidized ilmenite concentrate were measured by the method of microwave cavity perturbation. The effects of particle size, oxidation temperature and oxidation time on the microwave-absorbing characteristics were investigated. The particle size, oxidation temperature and oxidation time have substantial impact on the microwave-absorbing characteristics of the sample and therefore the microwave heating performance during the oxidation processes of the ilmenite concentrate. Results indicated that at the same oxidation time, the microwave absorbing characteristics decreased as the oxidation temperature increased, and at a constant temperature, the microwave absorbing characteristics of the sample decreased as the oxidation time increased. The microwave absorbing characteristics of the ilmenite concentrate with 80–120 mesh particle size was stronger than that of 200 mesh particle size. The microwave absorbing characteristics of products oxidized at 900 °C for 30 min were slightly weaker than those treated at 800 °C for 30 min and 900 °C for 20 min. The sample becomes less efficient in absorbing microwave energy as the oxidation proceeds. It is therefore recommended strong microwave absorbing materials or conventional heating be applied at the late stage of oxidation to aid microwave heating.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::44f7c30423c7169143bab54887123f10Test
https://doi.org/10.1515/htmp-2015-0048Test

المؤلفون: Huitao Chen, Jian Chen, Weiying Huang, Jianjun He, Yanjie Ren, Cong Li, Shengde Zhang, Wei Li, Lu Zuo

المصدر: Materials & Design, Vol 205, Iss, Pp 109729-(2021)

مصطلحات موضوعية: Nial, Materials science, Tensile properties, Annealing (metallurgy), Aluminized steel, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, 321 Austenite stainless steel, General Materials Science, Ductility, Microstructure, Materials of engineering and construction. Mechanics of materials, computer.programming_language, Mechanical Engineering, Metallurgy, Transgranular fracture, Intergranular corrosion, 021001 nanoscience & nanotechnology, Aluminizing, 0104 chemical sciences, Mechanics of Materials, TA401-492, engineering, Annealing treatment after aluminizing, 0210 nano-technology, Layer (electronics), computer

الوصف: In the present work, the tensile properties and microstructure of pack cementation preparing aluminized AISI 321 stainless steel with subsequent annealing treatment was investigated. The results reveal that the coatings of aluminized AISI 321 stainless steel are mainly composed of outermost Al2O3 layer, Fe-Al compound intermediate layer and Fe(Al,Cr) solid solution diffusion layer. The cross shape precipitate (NiAl) and strip precipitate (Ni3Al) are observed in Fe(Al,Cr) layer. After annealing, no new phase in aluminized coating is detected, meanwhile, the thickness of the aluminized coatings is increased and the porosity of Fe-Al layer is increased as well. In addition, the size of NiAl precipitates is decreased. The strength and plasticity of stainless steel are degraded by aluminizing treatment. However, after annealing, the aluminized steel exhibits a lower strength but a higher ductility. The crack initiation region of both aluminized steel with or without annealing treatment comprise coarse columnar grains and cleavage planes with river patterns. The fracture model of aluminized steel is cleavage fracture, while a mixed of intergranular and transgranular fracture is observed in aluminized annealed steel.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9383bf0e1c4b7f7b674eb4886f40eb56Test
https://doi.org/10.1016/j.matdes.2021.109729Test

المؤلفون: Qiu Mingquan, Wei Li, Bo Wu

المصدر: Shock and Vibration, Vol 2017 (2017)

مصطلحات موضوعية: 0209 industrial biotechnology, Engineering, Article Subject, 02 engineering and technology, law.invention, 020901 industrial engineering & automation, 0203 mechanical engineering, law, Control theory, Forensic engineering, Time domain, Civil and Structural Engineering, Weibull distribution, Downtime, Bearing (mechanical), Artificial neural network, business.industry, Mechanical Engineering, Failure rate, Geotechnical Engineering and Engineering Geology, Condensed Matter Physics, lcsh:QC1-999, Noise, 020303 mechanical engineering & transports, Mechanics of Materials, Prognostics, business, lcsh:Physics

الوصف: Aiming at reducing the production downtime and maintenance cost, prognostics and health management (PHM) of rotating machinery often includes the remaining useful life (RUL) prediction of bearings. In this paper, a method combining the generalized Weibull failure rate function (WFRF) and radial basis function (RBF) neural network is developed to deal with the RUL prediction of bearings. A novel indicator, namely, the power value on the sensitive frequency band (SFB), is proposed to track bearing degradation process. Generalized WFRF is used to fit the degradation indicator series to reduce the effect of noise and avoid areas of fluctuation in the time domain. RBF neural network is employed to predict the RUL of bearings with times and fitted power values at present and previous inspections as input. Meanwhile, the life percentage is selected as output. The performance of the proposed method is validated by an accelerated bearing run-to-failure experiment, and the results demonstrate the advantage of this method in achieving more accurate RUL prediction.

وصف الملف: text/xhtml

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1c785f35a5f50332146c1a8962122cc0Test
https://doi.org/10.1155/2017/8927937Test

المؤلفون: Qiang Li, Wei Li, Xiaoyu Huang, Baochao Zheng, Yangzhen Liu, Xiaohui Tu, Yanliang Yi

المصدر: Materials & Design, Vol 197, Iss, Pp 109164-(2021)

مصطلحات موضوعية: Materials science, Alloy, Modification, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, Adsorption, Boride, lcsh:TA401-492, General Materials Science, Composite material, Shape factor, Impact toughness, Mechanical Engineering, Abrasion resistance, 021001 nanoscience & nanotechnology, Microstructure, 0104 chemical sciences, Joint action, chemistry, Mechanics of Materials, engineering, lcsh:Materials of engineering and construction. Mechanics of materials, 0210 nano-technology

الوصف: Fe2B-type boride exists in Fe–B alloy with a form of netlike, rod-shaped, or fishbone structure. This results in high susceptibility of alloy to fracture. To improve the morphology of Fe2B, various contents of K2SO4 are added into an Fe-2wt%B alloy. The microstructure, mechanical properties and abrasion resistance of the modified alloy have been analyzed systematically.The results show that the α-MnS forms in the alloy, and increases with the increased K2SO4 in a relationship of y = 1.68× + 0.03. Moreover, the α-MnS can act as effective heterogeneous nuclei of M2B (where M represents Cr, Mn, and Fe), owing to a low lattice misfit of (111)α-MnS//(110)M2B. Meanwhile, the addition of element K can result in the formation of adsorbed film (K+ film) on the surface of M2B. By the joint action of α-MnS and K+ film, the structure of M2B changes from net-like into isolated block-shaped after heat treatment, and the shape factor K value of M2B increases from 0.13 to 0.44 with an increment of 241%. The change of M2B morphology effectively promotes an improvement of impact toughness and abrasion resistance of the alloy as a result.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0f905f0b836522a12e1caed0bc15a34eTest
https://doi.org/10.1016/j.matdes.2020.109164Test

المؤلفون: Xinying Wang, Binfang Meng, Jianghong Zhang, Wei Li

المصدر: High Temperature Materials and Processes, Vol 36, Iss 1, Pp 45-53 (2017)

مصطلحات موضوعية: 89.20.bb, Technology, Materials science, zinc coating, Chemicals: Manufacture, use, etc, chemistry.chemical_element, TP1-1185, 02 engineering and technology, Zinc, 81.15. ± z, engineering.material, 010402 general chemistry, 01 natural sciences, Corrosion, Coating, General Materials Science, Physical and Theoretical Chemistry, corrosion resistance, Chemical technology, 81.05. ± t, TP200-248, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, cerium, Cerium, chemistry, Chemical engineering, Mechanics of Materials, Conversion coating, sodium chloride, engineering, 0210 nano-technology

الوصف: The present paper investigated the impact of cerium on the corrosion resistance of zinc coating in a 5 % NaCl solution. Electrochemistry was used to measure the electrochemical parameters to compare the corrosion resistance of the zinc coating with that of the cerium conversion coating on the galvanized layer. SEM/EDS and XRD were adopted to analyze the appearance and phases of corrosion products of the cerium conversion coating and to probe the impact of cerium on the corrosion behavior of zinc coating in the Cl– media. The results showed that the cerium conversion coating formed on the zinc coating increased the zinc’s corrosion resistance effectively, conversion coating with lower cerium content protected the substrate poorly, resulting in easy erosion of the zinc coating in the Cl– media. The corrosion products mainly consist of complexes, such as Zn(OH)xCly and Ce(OH)xCly.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::3f4936e6061a183c18afce6b64517127Test
https://doi.org/10.1515/htmp-2015-0194Test