2015 Vol.35(2)

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2015, 35(2): 0-0.
[Abstract](87) [PDF 9319KB](2)
Advances in Large-Area Graphene Film Transfer Techniques
Mu CHEN, Yue YAN, Xiao-feng ZHANG, Wei-ming LIU, Chen ZHOU, Zhi-qiang GUO, Yong-lin WANG, Lei LI, Guan-li ZHANG
2015, 35(2): 1-11. doi: 10.11868/j.issn.1005-5053.2015.2.001
[Abstract](386) [FullText HTML] (142) [PDF 5437KB](28)
To realize large-scale applications of graphene films synthesized by chemical vapor deposition, technical breakthrough of transferring large-area graphene films is a prerequisite. This review focuses on recent advances in graphene transfer techniques, which are classified into mediator-assisted transfer, direct dry and wet transfer, mass production roll-to-roll transfer. The requirements and advantages of each class are described and compared from microscopic mechanisms to macroscopic operations. Mediator-assisted transfer is mainly used for lab scale exploration, the transferred films are of high quality but possess small sizes. Direct dry and wet transfer reduces the mediator transition process, but is still in bench scale. Mature roll-to-roll technique in semiconductor thin film industry is utilized in mass production roll-to-roll transfer, which realizes high efficient and repeatable pilot scale graphene film transfers. Mass production roll-to-roll is the most effective pathway to realize large-scale graphene film transfer.
Progress on Carbon Nanotubes in Health Monitoring of Polymer Composites
Shao-wei LU, Chun-lin FENG, Peng NIE, Xiao-qiang WANG, Xu-hai XIONG, Ke-ming MA
2015, 35(2): 12-20. doi: 10.11868/j.issn.1005-5053.2015.2.002
[Abstract](377) [FullText HTML] (64) [PDF 2265KB](13)
Carbon nanotubes have a widely potential application in health monitoring of polymer composites due to the excellent electromechanical properties. Research advances in carbon nanotubes sensing in polymer composites are reviewed: carbon nanotubes filler, carbon nanotubes coated fiber, carbon nanotubes yarn and carbon nanotubes paper. This paper also focuses on the analysis of the common core principle of carbon nanotubes sensing,namely using carbon nanotubes sensing network to monitor structural strain injury. Carbon nanotubes paper can resolve problems such as the hard dispersion in the blending of carbon nanotubes and resin, the collaborative deformation of carbon nanotubes coated fiber and the whole structure monitoring of carbon nanotubes yarn. Carbon nanotubes paper provides the engineering application condition for carbon nanotubes sensing. The engineering application of carbon nanotubes sensing in health monitoring of polymer composites is the future research direction.
Cellular Automaton Simulation of Dynamic Recrystallization for TC4-DT Titanium Alloy in β Hot Process
Cheng LIU, Hong-bo DONG
2015, 35(2): 21-27. doi: 10.11868/j.issn.1005-5053.2015.2.003
[Abstract](270) [FullText HTML] (47) [PDF 4322KB](3)
The TC4-DT titanium alloy dynamic recrystallization behavior was analyzed and cellular automaton (CA) model of dynamic recrystallization was established by isothermal constant strain rate compression tests in the β hot process. The microstructure evolution of TC4-DT titanium alloy was simulated on platform of DEFORM-3D using Cellular automaton. The simulated results show that the dynamic recrystallization behavior is more and more fully with the strain increased. The degree of dynamic recrystallization occurring at different regions of the sample is different. The dynamic recrystallization behavior of the central region is more fully and refines the original microstructure. The dynamic recrystallization behavior is inhibited with the increase of strain rate, but the grain size decreases. The simulation results agree well with the experimental results.
Flowage of Molten TiAl Based Alloy by Suction Casting
Xi-cong YE, Guang-wei ZHAO, Hai-hua WU, Jing-jie GUO, Yan-qing SU
2015, 35(2): 28-33. doi: 10.11868/j.issn.1005-5053.2015.2.004
[Abstract](263) [FullText HTML] (53) [PDF 4028KB](2)
The jet width, reverse filling position and reverse filling region for flowage of molten TiAl based alloy by suction casting was studied using simulation and experiment. Meanwhile, the process parameters were optimized. Results indicate that with the increase of suction diameter, the jet width of molten increases and the reverse filling is moved from the bottom to the top. The reverse filling region is also changed with the increase of the suction diameter. When the suction diameter is 4mm, the jet width and impression width are consistent, and reverse filling disappears. The good quality of TiAl based alloy sheet casting is obtained at the condition of suction casting at 1620℃ and the suction diameter of 4mm. The average size of cast microstructure is less than 50μm with the full lamellar.
Effects of Workpiece Mating Variations on 2219 Al Alloy Friction Stir Welding Process
Chao-lei LIU, Li ZHOU, Zhi-long CHANG, Hui-qiang WU, Yong-xian HUANG, Ji-cai FENG, Fan-xin MENG
2015, 35(2): 34-42. doi: 10.11868/j.issn.1005-5053.2015.2.005
[Abstract](296) [FullText HTML] (49) [PDF 4373KB](2)
The faying surface gap and misalignment in 2219 Al alloy friction stir welding were investigated. The microstructure and mechanical properties of the joint were discussed. Results show that the joint tensile strength decreases with the increase of faying surface gap under the optimized parameters of rotation speed 800r/min, welding speed 200mm/min and shoulder plunging depth of 0.3mm. Especially when faying surface gap width reaches 0.5mm,the joint tensile properties remarkably decrease. With the increase of pin tool offset from faying surface, the joint tensile properties decrease gradually, but the differences exist with the offset direction. The defects are formed at the bottom of the joint with pin tool offset of 2.0 mm from faying surface, which results in significant decrease of tensile properties.
Effects of Surface Treatment on Solid Particle Erosion Resistance of 17-4PH Stainless Steel
An-qi XIE, Dao-xin LIU, Ming-xia LIU, Hai-cun ZHANG, Xiao-hua ZHANG
2015, 35(2): 43-53. doi: 10.11868/j.issn.1005-5053.2015.2.006
[Abstract](244) [FullText HTML] (50) [PDF 5888KB](2)
Multi-arc ion plating ceramic/metal multilayers, laser surface alloying coating and high velocity oxy-fuel (HVOF) spraying hard ceramics coating were prepared on 17-4PH stainless steel to study the influence of surface treatment on solid particle erosion resistance 17-4PH stainless steel. Then, the failure mechanism of SPE at both low and high impingement angles of 17-4PH stainless steel and three kinds of coatings was studied by surface scratches tester and small energy multi-impact test machine. The results indicate that the main failure mechanism of the SPE at low impingement angle on 17-4PH stainless steel and coatings is the micro-cutting mode; but at a high angle, the main mechanism is the multi-impact fatigue failure mode. The SPE resistance of 17-4PH stainless steel at 30°and 90°impingement angles is remarkably improved by the HVOF WC-17Co coating. The laser alloying coating also enhances the SPE resistance of 17-4PH stainless steel at both 30°and 90°impingement angles respectively, but the comprehensive performance of the laser alloying coating is inferior than that of HVOF WC-17Co coating. However, the TiAlN/Ti multilayer does not improve the SPE resistance of 17-4PH stainless steel at 30°and 90°impingement angles.
Simulation of Local Corrosion on Metal Surface with CA Method
Le-ru HE, Zhi-ping YIN, Qi-qing HUANG, Jia-peng LIU
2015, 35(2): 54-63. doi: 10.11868/j.issn.1005-5053.2015.2.007
[Abstract](263) [FullText HTML] (51) [PDF 5155KB](2)
Cellular automata method was used to study the local corrosion of metals and cellular automata model framework of local corrosion was proposed. The metal-solvent system was dispersed into cellular grid, and local rules for metal corrosion involved in the transformation, penetration, diffusion process were defined. The parameterized model of corrosion rate including parameter φ, λ and ε was built. Matlab programming was used to realize the complex simulation of metal surface local corrosion with and without protective layer. When φ= 1, without protective layer, the morphology presents common uniform corrosion on the metal surface and various local corrosion appear in the inner metal. Whereas, under different λ and ε,the local corrosion metal surface takes on different morphology of pitting corrosion. Results show that the CA method can realize the complex simulation of metal surface local corrosion, and parametric model of λ and ε causes the differences of morphology.
Comparative Analysis of Microstructures and Properties of Two Kinds of Thick Plates of 7050-T7451 Aluminum Alloy
Feng ZHAO, Fa-yun LU, Fu-an GUO
2015, 35(2): 64-71. doi: 10.11868/j.issn.1005-5053.2015.2.008
[Abstract](264) [FullText HTML] (50) [PDF 3223KB](3)
Two kinds of 7050-T7451 aluminum alloy plate with the thickness of 61mm fabricated by two companies were investigated by optical microscope, scanning electron microscopy (SEM),room temperature tensile, fracture toughness and exfoliation corrosion tests, and the relations among the processing, microstructure and properties were discussed. The analysis results indicate that the comprehensive properties of both kinds of plates meet the requirements of AMS 4050H, but the strength and fracture toughness of one kind of plate are lower compared with the other, and the exfoliation corrosion performance is little higher. The property difference between these two kinds of plates comes from the better control of each process, which obtains more homogeneous microstructure along the thickness, lower recrystallization fraction,few residual Al7Cu2Fe particles with smaller size and uniform distribution and few Al2CuMg particles.
Effects of Barium Petroleum Sulfonate on Corrosion Resistance of Microwave Absorbing Coating
Xiao-wen JIANG, Zhen-jing JIANG, Da-qing HUANG
2015, 35(2): 72-76. doi: 10.11868/j.issn.1005-5053.2015.2.009
[Abstract](244) [FullText HTML] (52) [PDF 1597KB](2)
To improve corrosion resistance of the microwave absorbing coating filled with carbonyl iron powder, barium petroleum sulfonate (BPS), a kind of corrosive inhibitor, was added into the coating. The effect of mass percent of BPS on the capability of the corrosion resistance of the coating was studied using the neutral salt spray box, and the mechanism of corrosion resistance of BPS was analyzed. The effect of mass percent of BPS on mechanical strength and wave absorbing of coating were also discussed. When 4.2% (mass percent) of BPS was added into the coating, the capability of corrosion resistance of the coating was improved obviously. The surface of the coating becomes eighth grade (0.1%-0.25% of surface corroded) after 210h of being exposed in the salt spray box. The tensile strength of the coating was 4.3 MPa, and the reflectivity of the coating almost has no change.
Barrier Effect of Montmorillonitenano-Reinforcing Diphenyl Ether Phenylene Silicone Rubber
Jun-ying SUO, Fan LI, Lu-lu LI, Huang-hai QIAN, Li-jun CHENG
2015, 35(2): 77-82. doi: 10.11868/j.issn.1005-5053.2015.2.010
[Abstract](299) [FullText HTML] (53) [PDF 1708KB](2)
The structure, barrier effect of montmorillonite reinforcing diphenyl ether phenylene silicone rubber(DEP) were studied by FTIR,XRD, TEM and mechanical properties before and after the radiation. Results show that the organic montmorillonite(OMMT) is obtained after Na-MMT is inserted into the dioctyldecyltrimethylammonium bromide. Furthermore, the radiation resistance of OMMT/DEP composites is much better than those of the regular granule filler/DEP composites,and OMMT exists in the form of nano-intercalation. The radiation resistance, oil resistance and gas barrier properties of the nano OMMT/DEP composites are remarkably enhanced. The mechanism of multipath effect or nanowalls, which is due to barrier effect of OMMT layers is the profound reason.
Effects of Forming Process on Composite Stringer-Stiffened Panels Debonding
Mi ZHANG, Zhi-dong GUAN, Xia GUO, Bin XUE
2015, 35(2): 83-89. doi: 10.11868/j.issn.1005-5053.2015.2.011
[Abstract](262) [FullText HTML] (44) [PDF 3605KB](2)
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.
Evaluation of Mode I Stress Intensity Factor of Aramid Fiber Composite Materials Utilizing Digital Image Correlation Method
Wen-feng HAO, Xin-wen CHEN, Li-wei DENG, Xiang WANG, Xue-feng YAO
2015, 35(2): 90-95. doi: 10.11868/j.issn.1005-5053.2015.2.012
[Abstract](284) [FullText HTML] (61) [PDF 3542KB](6)
Digital image correlation method was used to study the fracture performance of aramid fiber composites. The principle of the digital image correlation method was described, and the relation between the crack tip displacement and the stress intensity factor was deduced using least squares fitting. The optical measurement system of digital image correlation method was established, and the full field displacement of the single-edge crack specimen was obtained experimentally. The stress intensity factor was extracted from the displacement field, and the effects of the number of terms, subset size and subset spacing on the calculation results were analysed. The results show that increasing the number of least squares fitting terms and reasonable selection of digital image correlation subset size improve the accuracy of calculated stress intensity factor.

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