Subjects: Materials Science >> Composite Material Subjects: Mechanics >> Solid Mechanics Subjects: Aviation & Aerospace >> Manufacture Technology of Aerocraft submitted time 2024-04-09
Abstract: The mechanical properties of unidirectional fiber-reinforced plastic (UD-FRP) are affected by internal micro-defects, such as random fiber arrangement, fiber misalignment, and micro#2;voids. This study aims to investigate how these multiple micro-defects interact with each other and how they affect the strength and failure mechanisms of UD-FRP through computational micromechanics. The failure behavior was simulated by the finite element analysis of a representative volume element; both matrix and interface failure were considered for the different loadings and their combinations. It was found that these micro-defects significantly weakened the compressive strength of UD-FRP along the longitudinal direction. Especially the fiber misalignment magnified the effect of fiber arrangement, while the micro-voids reduced the effect. Besides, the fiber arrangement and micro-voids significantly weakened the tensile and compressive strength of UD-FRP along the transverse direction. Moreover, transverse and longitudinal shear strengths are significantly affected by micro-voids, but only longitudinal shear is affected by fiber arrangement, and this effect is also weakened by micro-voids. Finally, the damage envelope under the combined longitudinal compression and transverse loads was obtained and compared with the Tsai-Wu failure criterion. The results showed that the Tsai-Wu criteria can provide an effective estimation for the failure locus under this biaxial loading condition.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Composite Material Subjects: Aviation & Aerospace >> Materials of Aviation & Aerospace submitted time 2024-04-09
Abstract: A generation algorithm of periodic high fidelity representative volume element (RVE) model of unidirectional fiber-reinforced composites (UD-FRP) is introduced. Firstly, based on the random walk algorithm, the fiber is characterized as the Bézier curve, and the tangent direction at each control point is adjusted to follow the multivariable von Mises Fischer function to generate a preliminary soft-core fiber network. Then based on the force-biased algorithm, the corresponding hard-core model is created by adjusting the overlap between fibers to ensure that the fibers in RVE do not twist excessively. In the adjustment process, a three-dimensional near-neighbor list is introduced to significantly improve the algorithm’s speed. Finally, the RVE containing fiber waviness is preliminarily calculated for transverse shear, so as to reveal the research value and application field of this method. The results show that the RVE of the required size and fiber waviness can be generated effectively and quickly by this method, the transverse shear strength of UD-FRP can be affected by the fiber configuration with waviness characteristics. The transverse shear strength of UD-FRP increases with the increase of fiber waviness.
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Materials Science >> Ceramics submitted time 2024-03-20
Abstract: The long-term structural stability of high-level radioactive wastes was the key for deep geological disposal under irradiation. In this work, 500 keV He2+ ion beams irradiation of zirconolite-2M, zirconolite-3O and zirconolite-4M three-type solid solutions were performed to study the structure damage from α decay in long-term deep geological disposal. All samples were synthesized through conventional high-temperature solid-state reaction at 1400℃ sintered twice 48h. The grazing incidence x-ray diffraction (GIXRD), Raman and x-ray photoelectron spectroscopy (XPS) results indicated that zirconlite-2M sample experienced crystalline phase evolution from zirconolite-2M to zirconolite-4M to disorder pyrochlore and amorphous with irradiation dose increased. For zirconolite-3O sample, the phase transformed to perovskite at 5×1015 ions/cm2 dose, and perovskite quickly transformed to disorder pyrochlore at higher dose. Disorder pyrochlore became major crystal structure when dose increased to 1×1017 ions/cm2. Zirconolite-4M remained with disorder pyrochlore or defect fluorite second phase under 1×1017 ions/cm2 irradiation. Summarily, the irradiation damage resistance of zirconolite-2M was similar with zirconolite-3O, and lower than zirconolite-4M.
Subjects: Physics >> Nuclear Physics Subjects: Astronomy >> Astronomical Instruments and Techniques Subjects: Materials Science >> Materials Science (General) submitted time 2023-12-15
Abstract: The GECAM series of satellites utilizes LaBr3(Ce), LaBr3(Ce,Sr), and NaI(Tl) crystals as sensitive materials for gamma-ray detectors (GRDs). To investigate the non-linearity in the detection of low-energy gamma rays and address the errors in the calibration of the E-C relationship, comprehensive tests and comparative studies of the three aforementioned crystals were conducted using Compton electrons, radioactive sources, and monoenergetic X-rays. The non-linearity test results of the Compton electrons and X-rays demonstrated substantial differences, with all three crystals presenting a higher non-linearity for X/γ-rays than for Compton electrons. Despite the LaBr3(Ce) and LaBr3(Ce,Sr) crystals having higher absolute light yields, they exhibited a noticeable non-linear decrease in the light yield, especially at energies below 400 keV. The NaI(Tl) crystal demonstrated an "excess" light output in the 6–200 keV range, reaching a maximum "excess" of 9.2% at 30 keV in the X-ray testing and up to 15.5% at 14 keV during Compton electron testing, indicating a significant advantage in the detection of low-energy gamma rays. Furthermore, we explored the underlying causes of the observed non-linearity in these crystals. This study not only elucidates the detector responses of GECAM, but also initiates a comprehensive investigation of the non-linearity of domestically produced lanthanum bromide and sodium iodide crystals.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-12-05
Abstract: This study synthesized copper-substituted lead apatite using the hydrothermal method, starting from hydroxyapatite precursors. For stability, it is recommended to maintain copper substitution below x=2 in the Pb10-xCux(PO4)O apatite. The introduction of copper appropriately reduces the lattice constant, in line with DFT theoretical calculations. Non-equilibrium heat treatment introduces additional charge carriers; oxygen-rich tempering shifts the sample to paramagnetism, while anaerobic tempering leads to complex and unique hysteresis loops. Non-equilibrium annealing can increase carrier concentration, but its efficacy is limited. Although some improvements have been observed, further exploration involving additional element doping or seeking interfaces with suitable conductive phases is needed to achieve superconductivity.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Electronic, Optical and Magnetic Materials submitted time 2023-10-26
Abstract: Triboelectric nanogenerators (TENGs) are promising self-powering supplies for a diverse range of intelligent sensing and monitoring devices, especially due to their capability of harvesting electric energy from low frequency and small-scale mechanical motions. Inspired by the fact that contact-separation mode TENGs with small contact areas harvest high electrical outputs due to fringing effect, this study employed discontinuity on the dielectric side of contact-separation mode TENGs to promote fringing electric fields for the enhancement of electrical outputs. The results reveal that the TENGs with more discontinuities show higher overall electric performance. Compared to pristine TENGs, the TENGs with cross discontinuities increased the surface charge by 50% and the power density by 114%. However, one should avoid generating discontinuities on tribonegative side of TENGs using metal blade within a positive-ion atmosphere due to the neutralization through electrically conductive metal blade. The computational simulation validated that the TENGs with discontinuities obtained higher electrical outputs, and further investigated the effect of discontinuity gap size and array distance on TENGs performance. This study has provided a promising method for the future design of TENGs using discontinuous structures.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Electronic, Optical and Magnetic Materials submitted time 2023-08-23 Cooperative journals: 《中国科学院院刊》
Abstract: 光谱覆盖广的突出优点,是助力实现光电子信息产业 突破的关键基础材料。为抢占“镓体系”半导体科技制高点,文章在分析“镓体系”半导体科技的战略意 义、重大需求和国内外发展态势基础上,从建制化科研组织、基础研究、自主可控的平台建设等方面对我国 发展“镓体系”半导体科技提出了政策建议。
Subjects: Materials Science >> Materials Science (General) submitted time 2023-08-14
Abstract: As a new type of building material, foamed concrete has main characteristics such as low density, good insulation, and good fireproofing, the advantages of waste use and use-cost are also introduced. In Chinese strategic policy and protection fields such as materials of walls and energy saving of building, more and more important influence it has own with these characteristics and advantages. Material composition, application of foamed concrete in this paper have introduced, especially a summary of the mixed proportion of practical application, the development of domestic and abroad are compared, and put forward some trouble of application of it, based on that, the future of foamed concrete has prospected. Meanwhile, from a personal view, the new application of foamed concrete is put forward.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The influence of short-term storage in dry atmosphere on the corrosion behavior of copper was investigated by means of potentiodynamic polarization, electrochemical impedance spectroscopy, capacitance measurement and array electrode technique. It was found that the surface film on copper presented a p-type semiconductor structure, and the carrier concentration decreased after short-term storage. At the same time, the corrosion potential increased, the corrosion current density decreased, and the surface film inhibited both the cathodic and anodic process. Copper displayed the typical characteristics of localized corrosion beneath a NaCl droplet. After storage, the wet-ability, the corrosion activity as well as the overall average corrosion intensity are reduced, but the local corrosion intensity enhanced.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: Original corrosion data, which were acquired by online detecting a buried oil and gas pipeline, were processed in accord with the Gumbel extreme value type I distribution, then a model for predicting the maximum corrosion depth is built to determine the possible maximum corrosion depth of the whole pipeline with the above method, a model for predicting the residual thickness of pipe wall is established to predict the residual life of oil and gas pipelines. In the end, as an example, the model was used to predict the residual life of a domestic pipeline in service, it is ca 19.95 a, which indicates that the predict result is correct and reasonable.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The microstructure and mechanical properties of the seawater corrosion resistant rebar steel 00Cr10MoV was investigated, while its corrosion resistance was studied by salt-spray test, periodical immersion test, electrochemical impedance spectroscopy and polarization curve measurements. The results show that the microstructure of 00Cr10MoV composed of ferrite and bainite with yield strength above 400 MPa. Compared with 20MnSiV, 00Cr10MoV had excellent corrosion resistance in simulated marine environment. The charge- transfer resistance of 00Cr10MoV was 1.37×105 Ω·cm2, 100 times more than 20MnSiV. Its corrosion products consist of major phases α-FeOOH, β-FeOOH and γ-FeOOH, minor phase Fe3O4 and trace phases Na3CrCl16 and Fe+3O(OH, Cl).
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The anti-corrosion performance of glass fiber reinforced plastic (GFRP) composites was evaluated by immersion test in 3.5% (mass fraction) sea salt solutions at 70 ℃ in terms of the decreasing trend of the pH value of the solution, the mass variation rate, and the bending strength retention rate of GFRP composites with time. While the surface morphology of the fractured surface of the composites, especially the glass fiber/resin interface before and after corrosion was examined by SEM. The concrete sample wrapped with GFRP composites was used to examine the timewhen Cl- penetrated through the GFRP layer. And, the life of resistance to Cl- penetration of 2 mm thick GFRP composites was predicted. Results showed that the life of resistance to Cl- penetration for the unsaturated ester based GFRP composite was about 30 a; while the epoxy vinyl ester based GFRP composite was about 70 a.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The corrosion behavior of pure aluminum A1060 in tropic marine environment was simulated by cyclic immersion test, while the correlation of the corresponding results of indoor cyclic immersion test and outdoor marine atmospheric corrosion test of A1060 was comparatively studied in terms of its corrosion morphology, corrosion products and corrosion kinetics by means of weight loss measurement scanning, electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results showed that the corrosion morphologies and phase constituents compositions of corrosion products after cyclic immersion test agreed fairly well with those after the real atmospheric test. Thereafter, a prediction model for the C corrosion prediction model of aluminum 1060 in two kinds of marine atmospheric environments, which aims to simulate the atmospheric environments at Wanning and Xisha areas in the South China Sea, was estab-lished built combined with Grey correlation method, while the corresponding arithmetic expressions could be described as follows i.e. TWN=146.7t 1.29 and TXS=862.3t 0.85 respectively.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The explosion of boiler tubes induced by the oxide scale causes a great influence on the safety and economy of power plants. The source of corrosion products in supercritical power plants is analyzed based on the physical and chemical properties of supercritical water, while the moving process of corrosion products can be described as follows: the corrosion products generated in the low pressure heaters and high pressure heaters, and then they are moving with the water. As the solubility of the corrosion products in the water was changed, which depended on both the pH and temperature, therewith the corrosion products deposit on the high temperature tubes. It follows from the analysis that the oxide scales on the boiler wall seem to be from two origins: the one is the high temperature corrosion of the tube wall itself, the other one is the deposition of corrosion products from upstream. Furthermore, the effect of the moving of corrosion products on the operation of power unit may be modified by properly inducing feed water of high quality in the steam-water system, thereby to ensure the safe and stable operation of the supercritical power unit.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The corrosion behavior of the boiler tail material which is made of carbon steel and stainless steel in solutions of ammonium bisulfate (ABS) and H2SO4 respectively was studied by means of mass loss measurement and potentiodynamic polarization curve as well as SEM/EDS and XPS. The results showed that: stainless steel has better corrosion resistance to ABS, and with the increase of ABS solution concentration, corrosion becomes more intensive. The corrosion products consist of Fe2O3, FeOOH, Fe3O4, iron sulfate and a small amount of iron carbon oxide. The corrosion process of carbon steel and stainless steel is similar in the solutions with the same concentration of ABS and sulfuric acid. It can be concluded that ABS has stronger corrosivity. The corrosion mechanism is that hydrogen depolarization first may occur during the corrosion of carbon steel, and then generate hydrogen. As the acid consumption, as well as the effect of dissolved oxygen in the solution, the oxygen depolarization corrosion will happen on metal surface, Fe2+ is then further oxidized to Fe3+, produces a series of secondary reaction, to generate iron oxide and sulfate, etc.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: Stainlesssteel 304 is being widely used in water supply system, and the dissolution of Cr6+ from materials of the system into tap water is one of the critical indexes of safety assessment. In the present work, different samples of stainless steel 304 components such as pipe, bar, plate, casting, and powder metallurgical product, were immersed in simulated tap water for 22 d, then the concentration of the dissolved Cr6+ in the water was determined by means of colorimetric of diphenylcarbazide with a spectrophotometer V-1800PC, while the microstructure of the samples before and after test was carefully examined by means of metallographic microscope MEF4A with image analysis system Q500 and SEM interms of morphology of grains, phase composition and distribution of inclusions etc. The results showed that the amount of dissolved Cr6+ versus time were quite different for sample to samples. The larger diameter and quantity of spherical inclusions in steels would be much favorable to the dissolution of Cr6+ for the same immersion period. In general, the spherical inclusions were complex oxides rich in Cr and Mn. In order to reveal the effect of MnO2 on the dissolution of Cr6+ from the steel, artificial inclusions of Cr2O3 and Cr2O3+MnO2 were introduced respectively into the steel by powder metallurgy, therewith the immersion test results showed that the dissolution of Cr6+ increased with the increasing amount of Cr2O3 and MnO2. These results confirm that the inclusions of Cr/Mn complex oxides play important role in the dissolution process of Cr6+, i.e. they are not only the source of Cr3+, but act also as oxidant to transform Cr3+ to Cr6+ in the Cl- contained solution. It can be inspired from these results that the Cr6+ dissolution could be significantly decreased by controlling the density and size of Cr/Mn oxides inclusions.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The effect of sulfate reducing bacteria (SRB) on stress corrosion cracking (SCC) behavior of X100 pipeline steel was investigated in artificial solution, which simulated the acid soil medium in the area of Yingtan at the Southeast China by means of slow strain rate test (SSRT) and scanning electron microscope (SEM). The results show that X100 pipeline steel has higher SCC susceptibility in the sterile artificial solution than that with SRB. The failure mode is transgranular cracking in both the two solutions. These results suggest that SRB inhibits the brittleness and reduces the SCC susceptibility of X100 pipeline steel, which may be ascribed to that SRB can breed rapidly and form a compact biofilm on X100 pipeline steel surface, then partly block the migration of corrosive Cl- onto the X100 steel surface.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The evolution of corrosion product film formed on X80 pipeline steel in artificial solution, which simulate the soil medium at Ku'erle area, with different immersion time was studied by immersion tests, while the morphology and phase constituent of the corrosion product film was characterized by means of scanning electron microscope (SEM) and X-ray diffraction (XRD) respectively. The effect of corrosion product film on the pitting corrosion of X80 pipeline steel was investigated by cyclic polarization curves and electrochemical impedance spectroscopy (EIS). The experimental results showed that the thickness and compactness of corrosion product film gradually increased with increasing immersion time. After immersion for 168 h, the corrosion product film was clearly divided into two layers. The pitting of X80 pipeline steel may be hindered or inhibited by the corrosion product film, which may reduce the probability of pitting initiation, and increase the resistance to pitting growth.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The copper phthalocyanine disulfonic acid CuPc-(SO3H)2 (CuPANI) was prepared with direct fast turquoise blue GL as raw material, and then the CuPANI doped polyaniline was obtained by chemical reaction of eigenstate polyaniline (EBPANI) with CuPc-(SO3H)2 in N,N′-dimethylformamide. The doped polyaniline was characterization by IR, UV-Vis and four point probe. The coatings with EBPANI or CuPANI as filler and epoxy resin 44 (EP-44) and 107 glue as adhesives were prepared on the surface of pretreated steel sheets, while the corrosion behavior of the sheets without and with coatings with EBPANI and CuPANI in 3.5%NaCl solution was investigated by electrochemical methods such as tafel polarization curve measurement, and alternating current impedance spectroscopy, respectively. The results indicated that the CuPANI doped polyaniline coating shows better anticorrosion performance.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The electrochemical behavior of three solvent- free epoxy coatings on Q345E carbon steel during corrosion-erosion induced by flowing slurry of simulated sea water with 1% (mass fraction) of sand at 60 ℃ was investigated by means of electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM), respectively. The results showed that the flowing slurry induced erosion aggravated the deterioration of coatings. The amine-cured epoxy powder coating and phenolic aldehyde amine-cured liquid epoxy coating were cured with slow speed and thus much densified, accordingly, their deterioration process experienced three stages: firstly, the inward migration of corrosive medium; secondly, the corrosion initiation of the substrate metal; thirdly, the corrosion propagation of the substrate metal beneath the coating and finally the failure of coatings. On the contrary, the phenolic aldehyde-cured epoxy powder coating was cured with fast speed and thus much porous, its deterioration process experienced two stages with a shortened second stage. Therefore,the existence of pores in the coating is one of the important factors for inducing failure of coatings during corrosion-erosion.