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Advanced Research on Composite Materials

Advanced Research on Composite Materials

Tribological Properties of Graphene-Fe 3O 4 Nanocomposite Materials

QIAO Yu-Lin;ZHAO Hai-Chao;ZANG Yan;ZHANG Qing

Journal of Inorganic Materials,Vol 30,No. 01

【Abstract】 Graphene-based Fe 3O 4 nanocomposite materials were prepared by the melthod of Liquid-phase Ultrasonic Exfoliation. Morphologies of nanocomposite materials were characterized by means of SEM and TEM. Its tribological properties as a pure water additive were investigated using multi-functional reciprocating friction and wear tester. The lubrication mechanism was discussed based on results of analyses of SEM, XPS. The results showed that the Fe 3O 4 nanoparticles with size of 20–90 nm were densely and randomly deposited on interlamination and surface of graphene sheets. The nanocomposite materials as a pure water additive displayed good friction-reducing and antiwear performance. Compared with pure water,the graphene-based Fe 3O 4 nanocomposite could reduce the friction coefficient of 26.7% and the wear volume of 35.4% under condition of 10 N of load and 0.01wt% of concentration. The prosperity was attributed to the effect of adsorption membrane and boundary lubrication film containing graphene and Fe 3O 4 which inhibited oxidation of Fe and reduce wear on the frictional surface.

Effect of the Interfacial Transition Zone on the Dynamic Macroscopic Mechanical Behavior of Concrete

DU Xiuli;JIN Liu

Earthquake Engineering and Engineering Dynamics,Vol 35,No. 01

【Abstract】 The global mechanical behavior of concrete is determined by its meso-/micro-scopic components. Concrete is regarded as a three-phase composite composed of aggregate, mortar matrix and interfacial transition zone (i.e., ITZ) herein. It is assumed that the aggregate is elastic, which would not be damaged, and the plasticity damaged model combined with the material strain-rate effect is employed to describe the mechanical properties of mortar matrix and the ITZ. To investigate the effect of the ITZ mechanical properties on the dynamic mechanical properties of concrete,a flexural-tensile sample of concrete beam, a double-edged notched concrete sample under uniaxial tension and a concrete sample subjected to uniaxial compression are employed. The numerical results indicate that the mechanical properties of the ITZ have an obvious influence on the failure mode and mechanical properties of concrete subjected to a lower loading rate. However,when the loading rate is very high (such as impact load whose nominal strain rate is larger than 50/s), the corresponding dynamic failure modes and the macroscopic mechanical properties of concrete are almost not affected by the mechanical properties of ITZ.

Evaluation of the stress intensity factor of the type I crack in aramid fiber composite materials utilizing digital image correlation method

HAO Wen-feng;CHEN Xin-wen;DENG Li-wei;WANG Xiang;YAO Xue-feng

Journal of Aeronautical Materials,Vol 35,No. 02

【Abstract】 Digital image correlation method was used to study the fracture performance of the aramid fiber composite materials. The principle of the digital image correlation method was introduced, and the relationship between the displacement field and the stress intensity factor at the crack tip was constructed. Through the establishment of the optical non-contact measurement system of the digital image correlation method, the full displacement field of the aramid fiber composite materials containing unilateral crack specimen was characterized experimentally. The stress intensity factor was extracted from the displacement field obtained through the digital image correlation method, and the influences of the number of terms in the least-squares fitting method, the size of the sub-region and the step length on the calculation results were analyzed. The results show that increasing the number of items in the least-squares fitting method and reasonable selection of the size of the sub-region and the step length in the digital image correlation calculation could improve the calculation accuracy of the stress intensity factor.

Effects of Forming Process on Composite Stringer-Stiffened Panels Debonding

ZHANG Mi;GUAN Zhi-dong;GUO Xia;XUE Bin

Journal of Aeronautical Materials,Vol 35,No. 02

【Abstract】 In order to research the effects of co-curing and secondary bonding on composite stringer-stiffened panels, the paper contrasted the difference between them in damage process and failure mechanism of I-shaped stringer-stiffened panels were contrasted. By conducting four-point bending tests and building finite element models, the load and location at the initial damage propagation of the structure were obtained. The results demonstrate that co-curing specimens have higher damage threshold and slower damage propagation, which bring better loading capacity. For co-curing specimens, failures happen at the interface of the skin and stiffener, and the core regions of the stringer also fail. However, secondary bonding specimens typically fail inside the glue. Considering about the difference of the two forming processes and asymmetry of the I-shaped stringer, the finite element model was established to simulate the damage effectively.

Microstructure and Mechanical Properties of C/C-ZrC Composites

SHEN Xue-Tao;LI Wei;LI Ke-Zhi

Journal of Inorganic Materials,Vol 30,No. 05

【Abstract】 C/C-ZrC composites were obtained by subsequent steps: immersing carbon felts into ZrOCl 2 aqueous solution, heat treatment, densification by thermal gradient chemical vapor infiltration with methane gas and graphitization. Three-point bending tests were performed to evaluate the mechanical properties of the composites. The results show that the flexural strength and elastic modulus increase with increasing Zr C contents. Carbon/carbon(C/C) composites containing 12.08 wt% ZrC achieve a flexural strength of 42.5 MPa and a modulus of 9.6 GPa, increasing by 70.0 % and 43.3 %, respectively, as comparison with the flexural strength and modulus of C/C composites. Micro-size ZrC particles with weak anchoring strength between them are unfavorable to the strength of carbon matrices, but they are not the main determinant of the strength of the composites. Submicro- and nano-size ZrC particles in carbon matrices owning good interface anchoring strength with carbon matrices can enhance the strength and elastic modulus of carbon matrices, improving the final mechanical properties of the composites.

Synthesis and Electrochemical Performance of Red Phosphorus/Carbon Composites

TIAN Li-Yuan;YAO Zhi-Heng;LI Feng;WANG Yong-Long;YE Shi-Hai

Journal of Inorganic Materials,Vol 30,No. 06

【Abstract】 Effect of different fabrication methods, composition of electrolytes and various carbon substrates on the electrochemical performance of red phosphorus/carbon composites were studied. The red phosphorus (red P)/active carbon (AC) composites synthesized via ball milling method exhibited a low coulombic efficiency and cyclic capacity in the initial cycle, meaning poor utilization ratio of red P. It was found that the optimal electrolyte was 1 mol/L Li PF_6 in an ethyl carbonate (EC)/ethyl methyl carbonate (EMC)/dimethyl carbonate (DMC) mixed solvent. Red P/conductive carbon black (BP2000) and red P/AC composites were synthesized by a vapor deposition method. The morphology, structure and electrochemical performance of the as-prepared composites were characterized by thermal gravity analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM), BET surface analysis and cyclic voltammetry (CV). Electrochemical results reveal that the red P/AC composite (45% P) has a good reversibility with charge/discharge potential plateau at 1.0 V and 0.75 V. The initial discharge/charge special capacity is 1 500 and 1 200 m Ah/g (calculated based on the weight of composites), respectively, showing initial coulombic efficiency of 82.5%. In the subsequent cycles the coulombic efficiency is over 97.5%. The stable cyclic capacity is related to 2.8-electron reaction. Relying on the stable discharge capacity in the second cycle, the capacity retention is 75.0% after 50 cycles. The as-prepared red P/AC composites exhibit high cyclic capacity and good cyclic stability, which can be attributed to the uniform dispersion of amorphous red P in the porous structure of AC substrate, especially in the micropores.

Effect of B 2O 3 Doping and Phosphate Impregnation on Oxidation Resistance and Mechanical Properties of Mesocarbon Microbead Composites

LEI Zhuo-Yan;WANG Zhi;FAN Heng-Bing;MA Wen-Bin;CHEN Jian;WANG Xu

Journal of Inorganic Materials,Vol 30,No. 07

【Abstract】 Mesocarbon microbead/carbon nanotubes(MCMB/CNTs) composites were modified by adding B_2O_3 powders and phosphate impregnation and the MCMB/CNTs were prepared using in-situ thermal polymerization. The morphology, flexural strength and oxidation resistance behavior were studied using scanning electron microscope(SEM), three-point bending tests, thermo gravimetric analysis(TG) and isothermal oxidation method. The results show that the oxidation resistance and flexural strength of the composites are enhanced with proper amount of B_2O_3. When the ratio of B_2O_3 is beyond 2%, the flexural strength of the sample begins to decrease. The sample with 2% B_2O_3 impegnated with phosphate reachs the highest flexural strength of 66 MPa, and the initial mass loss temperature of the samples is 520℃. After isothermal oxidation at 500℃ for 60 min, the mass loss and the flexural strength of the sample are 5% and 50.3 MPa, respectively.

Properties of a Lens-focused Transducer Based on Piezoelectric Composites

HE Min;HAO Qi;WANG Ke-Xin;ZENG De-Ping;YE Fang-Wei;LI Fa-Qi;WANG Zhi-Biao;HE Hong-Ying

Journal of Inorganic Materials,Vol 30,No. 07

【Abstract】 To broaden the bandwidth of focused transducer with suppressing the multi-mode coupling phenomenon, and improving the electro-acoustic conversion efficiency, 1-3 piezoelectric composites as the ultrasonic emission material was used to replace Pb-based lanthanum doped zirconate titanates ceramic. A new type of lens-focused transducer was designed and produced based on 1-3 piezoelectric composites. Through the comparative study of frequency characteristic, it is proved that the 1-3 piezoelectric composites lens-focused transducer can not only increase the bandwidth of the transducer which is 3.13 times higher than of the one based on Pb-based lanthanum doped zirconate titanates, but also suppress the radial vibration obviously to obtain a single pure vibration modes. Besides, the electro-acoustic conversion efficiency of the former lens-focused transducer is 1.88 times higher than the latter one. These results provide a theoretical and experimental foundation for the realization of ultrasonic transducer of high efficiency on reliability and stability.

Preparation and Electrical Properties of Graphene Coated Glass Fiber Composites

LIU Guo-Qiang;SHI Fu-Zhi;LI Yao-Gang;ZHANG Qing-Hong;WANG Hong-Zhi

Journal of Inorganic Materials,Vol 30,No. 07

【Abstract】 The graphene coated glass fiber composites were obtained from the electrostatic adsorption of graphene oxide on bovine serum albumin (BSA) modified the glass fibers, and the subsequent reduction of graphene oxide coated glass fibers by hydroiodic acid at low temperature of 40 °C. The phase structure and functional groups of graphene oxide were studied by XRD and FT-IR, respectively. SEM images showed that the graphene wrapped effect was improved with pH decreasing, when pH of graphene oxide dispersion was less than 6. Zeta potential of graphene oxide and BSA molecule were tested by Particle size/Zeta potential instrument, which showed that the isoelectric points of graphene oxide and BSA were smaller than 3 and 5.3, respectively. Conductivity of graphene wrapped glass fiber composites reached 4.5 S/m, and conductive glass fibers maintained original conductivity after different levels of bending. Moreover, due to the reduction of graphene, the conductivity increased slightly after the heat-treatment above 100 °C. These results prove that the conductive glass fibers can be used at high temperature.

Low-velocity Impact Damage and Compression Failure Behavior of Plain Woven Composite Laminate

MA Shao-hua;GUO Hong-jie;HUI Li;WANG Yong-gang

Journal of Aeronautical Materials,Vol 35,No. 04

【Abstract】 Based on the low-velocity impact test and the compression test after impact on plain woven composite laminate at different impact energy, the relationships among the energy of impact, dent depth, damage area and residual compress strength were analyzed. The effect of different impact damage on the characteristic of compression failure through macroscopical observation at the side of the fracture on the compressed laminate was studied. Results show that impact damage includes non-damage, barely visible impact damage (BVID), visible impact damage (VID) and penetrating damage, and different damage grades have different failure characteristics. With the increase of impact energy, the dent depth increases gradually, but the relationship is not linear because of a knee point; the damage areas also increase gradually, and remain the same after reaching the penetrating damage; the residual compress strength decreases gradually. Finally both the damage areas and the residual compress strength tend to change slowly.

Preparation and Visible Light Responsive Photocatalytic Activity of Bi 2MoO 6/Ni-Fe LDH Composites

QU Ting;HUANG Qiang;ZHAO Zhen-Bo

Journal of Inorganic Materials,Vol 30,No. 08

【Abstract】 Bi 2MoO 6/Ni-Fe LDH composites were prepared by hydrothermal method and co-precipitation. The morphology and structure of the sample were characterized by XRD, FT-IR, SEM, TEM, XPS and N 2-physisorption. Photocatalytic degradation activity and mechanism of the samples were investigated by the photocatalytic degradation of methyl orange(MO), methylene blue, butyl rhodamine B and phenol under visible light irradiation. The results showed that BET specific surface area of the composites increased with the LDH content increase. Photocatalytic degradation activity of MO under visible irradiation exhibited significant enhancement. After visible light irradiation for 60 min, the Bi 2MoO 6/Ni-Fe LDH composites with LDH content of 4.5wt% showed the highest degradation rate of 91%, higher than that of Bi 2MoO 6 and Ni-Fe LDH by 52% and 16%, respectively. And t he composites photocatalytic degradation followed first-order reaction kinetics. The composites decolorizing rate still remained 88% after 5 times recycle, showing high catalytic stability.

Nitrogen Doped Carbon Quantum Dots/Titanium Dioxide Composites for Hydrogen Evolution under Sunlight

WEI Jie;LI Xue-Dong;WANG Hong-Zhi;ZHANG Qing-Hong;LI Yao-Gang

Journal of Inorganic Materials,Vol 30,No. 09

【Abstract】 Using acetonitrile as the solvent and glucose as the raw material, nitrogen doped carbon quantum dots (NCDs) were prepared by the solvothermal method. The size of NCDs is around 4 nm. The emission spectrum of NCDs showed red shift when the excitation wavelength of quantum dots increased from 330 nm to 470 nm. Titanium dioxide was coated by NCDs by mixing a certain proportion of NCDs, TiO 2 and ultrapure water through 60 min ultrasonic and aging under 80 °C for 24 h. NCDs/titanium dioxide composites show good photocatalyst performance as compared with pure NCDs and pure titanium dioxide, because the NCDs can expand the absorption spectrum and reduce the photogenerated electrons and holes. The NCDs/TiO 2 composites at the raw ratio of m(NCDs):m(TiO 2) = 15:85 show the best hydrogen evolution performance, using methanol as the sacrificial agent. The composite material displays good stability and certain photocatalytic performance after three cycles.

Magnesium Phosphate/PBS/Wheat Protein Biocomposite for Bone Repair

WANG Quan-Xiang;WU Ying-Yang;DONG Xie-Ping;MA Xu-Hui;WEI Jie

Journal of Inorganic Materials,Vol 30,No. 09

【Abstract】 Magnesium phosphate was prepared through coprecipitation method, and biocomposite containing magnesium phosphate (MP), polybutylene succinate (PBS) and wheat protein (WP) was fabricated. In vitro degradability, bioactivity and cell responses to MP/PBS/WP composite were investigated. The results showed that the pH value changed from 7.4 to 7.51 after the MP/PBS/WP composite being soaked in Tris-HCl buffer solution for 10 d. The weight loss of the composite reached 58.43 wt% after soaking for 12 w. Apatite layer could form on the composite surfaces after soaking in SBF solution for 10 d, indicating good bioactivity. In addition, the MP/PBS/WP composite could promote proliferation and differentiation of MC3T3-E1 cells. All data from this study show that the MP/PBS/WP composite has good degradability, bioactivity and cytocompatibility, showing a potential to be used as a new biomaterial for bone repair.

Research on Lamb wave imaging technique for composite plate based on chirp excitation

Liu Zenghua;Mu Yunlong;Song Guorong;He Cunfu;Wu Bin

Chinese Journal of Scientific Instrument,Vol 36,No. 09

【Abstract】 As a rapid and efficient nondestructive testing method, Lamb wave technology possesses great application potentials in structural health monitoring fields and has been paid considerable attention. In this paper, the wide-band linear chirp signal is chosen as the excitation signal to replace traditional narrow band tone burst signal. Through post-processing,the response signal of the chirp signal can be demodulated, and the equivalent tone burst response signals with any center frequencies in the bandwidth range of the chirp signal can be extracted. A kind of piezoelectric transducer is designed optimally, which can excite and receive the pure A 0 mode signal in low frequency range. The A 0 mode signal is very sensitive to the defects in plates, which makes the signal to be analyzed more conveniently.These developed piezoelectric transducers were arranged on a quasi-isotropic composite plate sparsely, and the simulated faults were detected. The detection data of the chirp signal obtained in the experiment were demodulated, and the response signals with multiple center frequencies were achieved. The elliptic imaging technique and data fusion method were combined to perform defect imaging, and the defect location in the composite plate was realized. The imaging results from the signal fusion of the response signals with multiple frequencies have higher resolution, contrast and location accuracy.

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