Papers by Author: Xiao Dong He

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Authors: Zhong Hai Xu, Rong Guo Wang, Wen Bo Liu, Cheng Qin Dai, Lu Zhang, Xiao Dong He
Abstract: In this paper, we predict the delamination buckling behavior in slender laminated composite with embedded delamination under compressive load by using the finite element method (FEM). For the different delamination size and depth position, we illustrate the various parameters effects on buckling behavior.
Authors: Jian Guang Zhang, Xiao Dong He
Abstract: Joining behavior of long glass fiber reinforced polypropylene (LFT) by three types of adhesive was investigated. Single-lap shear testing was used to evaluate the performance of adhesively bonded structures. The two-part acrylic adhesive DP8005 was determined to be the best among the three adhesive candidates, which was attributed to its low surface energy. The stress distribution in the adhesive layer of the single lap joint was modeled by static elastic analysis using ANSYS software. The shear and peel stresses peaked at the edges of the adhesive layer.
Authors: J.Z. Zhang, Xiao Dong He, Shan Yi Du
Authors: Ye Sheng Zhong, Xiao Dong He, Jia Yu, Li Ping Shi
Abstract: Microarc oxidation (MAO) is a relatively convenient and effective technique to deposit ceramic coatings on the surfaces of Al, Ti, Mg and their alloys. This technique can introduce various desired elements into titania-based coatings and produce various functional coatings with a porous structure. Microarc oxidized (MAO) TiO2-based coatings on titanium alloy were formed in electrolytes containing aluminate and ZrO2 particles. The phase composition of the samples was analyzed by glance-angle X-ray diffraction and the surface morphologies of the samples were observed by a scanning electron microscopy (SEM). In addition, the element concentrations on the surfaces of the samples were measured by an energy dispersive X-ray spectrometer. The experiment results indicated that: MAO coatings, which are porous structures and exhibit good interfacial bonding to the substrate, may possess specific surface structures such as crystal phase, non-equilibrium solid and complex mixed-compounds since complex plasma physical and chemical reactions.
Authors: Xiao Dong He, He Xin Zhang, Yao Li, Chang Qing Hong
Abstract: Highly Nano-porous SiO2-ZrO2 aerogels were manufactured with tetraethylorthosilicate (TEOS) and zirconyl nitrate dihydrate (ZrO(NO3)2 .5H2O) by the sol-gel method followed by supercritical drying technique. The prepared aerogels are performed by SEM, FT-IR and BET to characterize and analyze the morphology and pore structure of SiO2-ZrO2 aerogels. The results showed that:(i) The areogels are the typical of nano pores in the interval between 1
Authors: Chang Qing Hong, Xing Hong Zhang, Jie Cai Han, Qiang Xu, Xiao Dong He
Abstract: TiB2 -Cu cermet with the relative density of 92% was produced from titanium, boron and copper powders by combustion synthesis and subsequently pseudo hot isostatic pressing. To improve its mechanical and thermal physical properties, the two-time hot pressing sintering test was carried out at 1050°, 1090° and 1150°C respectively. The deformation behavior and variation of micro- structure and mechanical properties were investigated in detail. The results showed that the relative density and the flexural strength increase remarkably after two-time hot pressing. The relative density reaches 605.5MPa and the flexural strength reaches 96% when the two-time pressing temperature is at 1090°C, and the values increase 12% and 6% compared to that before two-time pressing.
Authors: Qiu Ming Zhang, Xiao Dong He, Yao Li
Abstract: Quartzite microcrystallite glass ceramics is one of the most promising machinable ceramic materials due to its many outstanding properties. The density of quartzite microcrystallite glass ceramics is smaller than the aluminum alloy and its thermal conductivity approaches to the zirconia and its elastic module is also very small; All these advantages meet the requirements for structural components to work at higher temperature; Compressive properties of quartzite microcrystallite glass ceramics had been studied at room temperature and 500°C in this paper; The specimens had been aged at 1000°C for 5, 10, 20, 30 hours, respectively. Through SEM observations of the fracture surface of the specimens, the microstructural changes had been determined; The tests showed: the compressive property of the machinable glass ceramic declined as the ageing time increasing; but the compressive property of the specimen aged for 10 hours was inferior to that aged for 20 hours; Then compressive property declined as the ageing time increasing. The SEM observation indicated that with the extend of ageing time, the grains grew bigger and microporous and microcracks increased in the specimens; Comparing the compressive property at room temperature with that at 500°C, one found that the change of compressive property was very small when the ageing time was the same; With the extend of ageing time, the curve of the compressive property changed from smooth curves to broken lines.
Authors: Rong Guo Wang, Wen Bo Liu, Fei Hu Zhang, Xiao Dong He, H.Y. Li
Authors: Guang Pin Song, Xiao Dong He, Yue Sun, Ming Wei Li
Abstract: Large scale Ni-based alloy sheets are prepared by electron beam physical vapor deposition with and without tungsten added into melting pools respectively. Addition W increased vapor rate and decreased compositional transformation during deposition. Chemical constitution of the sheet prepared through tungsten is more similar to that of the ingot. Microstructure of two alloy sheets is observed by scanning electron microscope (SEM) and atom force microscope (AFM). The results show that both of the sheets consist of columnar grains, whose major axes are almost parallel to the normal direction of the sheet. However, the average diameter of grains of the sheet through tungsten is larger than that of the sheet not through tungsten in minor axis direction. Mechanical properties and failure mechanisms of both sheets are studied. Tensile tests are conducted on a number of specimens. Strength, strain-to-failure are estimated under loading condition. The results show that the sheet prepared by EB-PVD through tungsten has a superior strength and an elongation percentage than that of the one prepared without tungsten.
Authors: Ying Chun Shan, Jiu Jun Xu, Xiao Dong He, Ming Wei Li
Abstract: A 2D kinetic Monte Carlo (KMC) simulation has been applied to study the microstructure of Ni-Cr film deposited by physical vapor deposition (PVD) for variable incident angle. In the KMC method, two phenomena were incorporated: adatom-surface collision and adatom diffusion, the interaction between atoms was described by embedded atom method and jumping energy was calculated by molecular statics calculations, initial location of adatom was located by Momentum Scheme. The results reveal that there exists critical incident angle, which is 35˚ for Ni-Cr thin film. When incident angle is less than 35˚, incident angle have less affect on surface roughness factor and packing density, compact films with smooth surface are obtained, their surface roughness factor is bellow 1.12 and packing density is more than 99.6%. However, when incident angle is more than 35˚, surface roughness factor increases quickly and packing density decreases sharply with incident angle increasing: surface roughness factor increase to 1.5 and 2.3 for incident angle of 45˚ and 60˚ respectively, packing density is below 99% and 96% accordingly. Which reveal that the self-shadowing effect emphasizes with incident angle increasing when the incident angle is more than 35˚.
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