Supervisor(s): China Association for Science and Technology Sponsor(s): Chinese Society of Aeronautics and Astronautics (CSAA); AVIC Beijing Institute of Aeronautical Materials (BIAM) CN：11-3159/V
Journal of Aeronautical Materials is supervised by China Association for Science and Technology, and sponsored by Chinese Society of Aeronautics and Astronautics (CSAA) and AVIC Beijing Institute of Aeronautical Materials (BIAM). The journal provides the latest academic researches regarding Chinese aeronautic and astronautic materials, in order to promote aeronautic and astronautic technologies, make a platform for scientific researchers, and push forward the progress of aeronautic and astronautic materials. Its scope covers aeronautic and astronautic materials, preparation processing, calculation, simulation, properties and characterization of materials. It also reviews on aeronautic and astronautic materials with promising applications.
The journal is included in CA, SA, Pж(AJ), CSCD.
Editor-in-Chief Dai Shenglong
Associate Editor Cao Chunxiao, Tao Chunhu, Lian Jianmin, Jin Haipeng
Damage effects of electron irradiation with different energies on mechanical properties of polyethylene heat-shrinkable sleeves were studied by irradiating the sleeves with 45 keV,1 MeV and 2 MeV electrons respectively. The mechanical property degradations of the sleeves before and after radiations were present. X-ray photoelectron spectra (XPS), scanning electronic microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to analyze the element contents, the morphologies and the molecular structures of the samples to study the damage mechanism of the sleeves. A degradation model for the changes of the mechanical properties of the sleeves in electron radiation environment was proposed. It is shown that the increase of irradiation degradation of the polyethylene causes the sleeves' mechanical properties. For the penetration depth of different energy electrons in polyethylene is different, only a shallow layer the sleeves is affected by 45 keV energy electrons, while 1 MeV and 2 MeV energy electrons are penetrated the sleeves and cause the sleeves great damage. The mechanical properties of the sleeves are decreased by about 30% to 40% after 45 keV energy electron irradiation, and decreased by about 100% after 1 MeV and 2 MeV energy electron irradiation.
TiO2-based UV detectors with Ag antidot/TiO2/ITO sandwich structure were prepared by RF magnetron sputtering and colloidal crystal template technology. The microstructure and photoelectronic properties of the UV detectors were investigated by SEM, XRD, four point probe and semiconductor parameter instrument. The experimental results show that pore size of Ag antidot has an obvious effect on the photoelectronic properties of the detectors. With the increase of pore size, the dark current increases and the response time is prolonged, while the photocurrent is increased at first, then is decreased. Meanwhile, it is found that photoelectronic properties are optimum when the pore size is 4.2 μm. Antidot array electrodes with large pore size possess higher electrical conductivity, lower ultraviolet transmittance and higher recombination probability of electron-hole pair. Therefore, the pore size variation exhibits significant influence on the photoelectronic properties of the UV detector.
The effect of sliding distances on aluminum matrix composite reinforced by silicon carbide particle with volume fraction of 9% was investigated. Friction behavior and wear resistance of the composite with distances of 5 000 r, 10 000 r and 20 000 r were studied under dry sliding conditions of the same speed and load (200 r/min, 45 N). The results show that the friction coefficient in long-range sliding process displays three stages: wearing zone, stable zone and accelerating zone. The matrix surface produces severe adhesion because of the rising temperature and then leads plastic areas, in which both friction coefficient and wear rate are increased.
Self-corrosion and pitting corrosion of 7B04 aluminum alloy at different environment conditions were studied by electrochemical test with simulating surface coating damage on 7B04 aluminum alloy. The forming conditions of pitting corrosion after contacting 7B04 aluminum alloy with TA15 titanium alloy were analyzed by finite element method which was based on the mathematical model of galvanic corrosion. The results indicate that the pitting potential of 7B04 aluminum alloy is influenced by Cl -concentration and pH value. Pitting corrosion of 7B04 aluminum alloy in self-corrosion condition can occur in neutral solution (mass fraction of NaCl>5%) or in acidic solution (mass fraction of NaCl=3.5%). The potential rises when 7B04 aluminum alloy contacts with TA15 titanium alloy which results in the occurrence probability of pitting corrosion. The occurrence probability of pitting corrosion is increased. The pitting corrosion of 7B04 aluminum alloy initiates and propagates when the area ratio of cathode to anode is greater than 40 in neutral solution (mass fraction of NaCl=3.5%). The potential of 7B04 aluminum alloy decreases slowly with the increase of the distance between cathode and anode, and the decline of the potential is not over 2 mV at distance within 10 m.
FeNiCrAl coating is a kind of surface wear resistant material for shaft parts. Microstructure, adhesive strength, phase composition and microhardness were analyzed in order to study the influence mechanism of spraying parameters on coating properties. The relation among the spraying current, coating microstructure and adhesive strength was studied in detail. The results show that the spraying current is very important to obtain the dense coating (porosity of 8.76%) with adhesive strength of 52.3 MPa and an excellent coating is prepared by spraying current 200 A, spraying voltage 34 V and spraying distance 160 mm. The hardness of the coating is 626 HV0.1 and about 1.6 times as that of the matrix. The effective mechanism is relevant to the scattering distribution of the Fe-Al intermetallic compound and Cr0.19Fe0.1Ni0.11 solution in the coating.
The superplastic tensile tests of TC6 alloy were conducted in the temperature range of 800–900 °C by using the maximum m value superplasticity deformation (Max m SPD) method and the constant strain rate deformation method with the strain rate range of 0.000 1–0.1 s −1. The stress-strain curve of the tensile tests was obtained and the microstructure near the fracture were analyzed by metallographic microscope. The result shows that the superplasticity of TC6 alloy is excellent, and the elongation increases first and then decreases with the increase of strain rate or temperature. When the temperature is 850 °C and strain rate is 0.001 s −1 in constant stain rate tensile tests, the elongation reaches up to 993%. However, the elongation using Max m SPD method at 850 °C is 1 353%. It is shown that the material can achieve better superplasticity by using Max m SPD tensile compared to constant stain rate tensile under the same temperature. The superplastic deformation of TC6 alloy can enhance the dynamic recrystallization behavior significantly, and the dynamic recrystallization behavior is promoted when strain rate and temperature are increased.
Inhomogeneity of microstructure and properties of 7085-T651 aluminum alloy extra-thick plate were investigated by tensile properties, exfoliation corrosion, optical microscopy (OM), composition analysis, scanning electron microscopy (SEM), differentia scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that the microstructure, tensile property and exfoliation corrosion in different layers of 7085-T651 aluminum alloy of 110 mm thick are inhomogeneous. For the 1/4 thickness layer, the tensile strength is the minimum, 540 MPa, and the resistance to exfoliation corrosion of this layer is the worst, with exfoliation corrosion classification of EB. For the core layer, the tensile strength is the maximum, 580 MPa. The resistance to exfoliation corrosion of the surface layer is the best, with exfoliation corrosion classification of EA. For the 1/4 thickness layer, it has the largest recrystallized fraction up to about 47.7% and the grain size is about 105 μm; there are equilibrium phase particles precipitated on grain boundaries or within grains; the size of aging precipitates is small; and thus both mechanical properties and resistance to exfoliation corrosion are the worst. For the core layer, it has the smallest recrystallized fraction of about 14.8% and there are a large number of sub-grains; the fraction of residual phase Al7Cu2Fe almost reaches up to about 1.43%; the size of the equilibrium phase on grain boundaries, the size of aging precipitates and the width of PFZ are large, and therefore good mechanical properties and bad resistance to exfoliation corrosion are obtained.
The hot deformation behavior of AA-FGH95 superalloy was investigated by hot compressive tests on Gleeble-1500D therma simulation test machine in different temperatures and strain rates. The true stress-strain curves were obtained, and based on the deformation data, the constitutive equation and processing map of FGH95 superalloy were built. The deformation active energy of AA-FGH95 is Q=695.78 kJ/mol. The results show that the simulated maximum stresses are in agreement with the experimental data, and the average error is about 6%. Based on the processing map, the safety processing parameters of 1 070-1 100 °C and 0.01-0.001 s -1 are confirmed. When the temperature reached 1 100 °C, the maximum strain rate increased to 0.5 s -1.
Structural stabilities, mechanical properties and electronic structures of Al2Cu, Al2CuMg and MgZn2 intermetallics in Al-ZnMg-Cu aluminum alloys were determined from the first-principle calculations by VASP based on the density functional theory. The results show that the cohesive energy (Ecoh) decreases in the order MgZn2 > Al2CuMg > Al2Cu, whereas the formation enthalpy (ΔH) decreases in the order MgZn2 > Al2Cu > Al2Cu Mg. Al2Cu can act as a strengthening phase for its ductile and high Young’s modulus. The Al2CuMg phase exhibits elastic anisotropy and may act as a crack initiation point. MgZn2 has good plasticity and low melting point, which is the main strengthening phase in the Al-Zn-Mg-Cu aluminum alloys. Metallic bonding mode coexists with a fractional ionic interaction in Al2Cu, Al2CuMg and MgZn2, and that improves the structural stability. In order to improve the alloys’ performance further, the generation of MgZn2 phase should be promoted by increasing Zn content while Mg and Cu contents are decreased properly.
The influence of acid etching time on wettability of ion-exchanged aluminosilicate float glass was investigated. The contac angle, roughness and surface composition were measured. The results show that the contact angle increases to a maximum value in the first 7 min and then decreases with the corrosion time. The main reason that causes the change of the contact angle is the change of surface roughness and the content of fluorine atom. The contact angle on the tin side is always larger than that on the air side which is caused by the tin ions on the tin side.
