Advanced Materials Research Vols. 311-313

Abstract: The aging behavior of Cu-0.39Cr-0.11Zr-0.12Y alloy was investigated in this paper. The results showed that the tested alloy could obtain higher electrical conductivity and microhardness in solution at 960 °C for 1 hour under various deformations and aging at 480 °C condition than that of the alloy in solution-aged condition. The strength of the tested alloy increased with the increased deformation by cold working, the highest tensile strength value reached 637 MPa, while the elongation and electrical conductivity dropped a little. The values of tensile strength, electrical conductivity and elongation were 603 MPa, 79.66%IACS and 9.8% respectively when the second pulling deformation increased to 75.0%, that would meet the requirement of contract wire used in electrical high-speed railway.

Abstract: In order to achieve the design of mechatronic system rapidly, an integrated design process is used for a hydrostatic slideway driven by linear motor. Control model of the linear motor and FE model of the slideway carriage are established, besides, force analysis of the carriage and relevant optimization are carried out. Software Simulink is used to simulate the linear feeding system. Subsequently, the advantages of the integrated design compared with traditional method are analyzed. This study could provide important insights for the design of the hydrostatic slideway with linear motor driven system.

Abstract: By the uniaxial tensile tests of both the arc and tube section samples, the strain hardening curves of 21-6-9 high-strength stainless steel tube(HSST) are obtained. Considering that the uniform plastic deformation stage of the curve is short and the flow stress in large strain area is unknown for this tube, different strain hardening models have been established based on single and piecewise functions, respectively. By comparing the experimental results and the numerical ones in terms of load-displacement curves, it shows the constitutive model achieved by three Swift fitting functions can better characterize the strain hardening response of the 21-6-9 HSST in large strain region.

Abstract: Transient temperature-fields of carbon fiber composites which contained defects were numerically simulated. When the total heat was constant, the influences of different pulse heating methods on thermal imaging temperature difference and contrast of carbon fiber composites surface were analyzed. The peak values of temperature difference and contrast declined progressively with the progressive decrease of heat flux, and all the peak values postponed. With the increase of initial heat and the decrease of second heat, the peak values of temperature difference and contrast increased progressively at the first emergence, and declined progressively at the second emergence. With the progressive increase of interval, the extreme values of temperature difference and contrast were almost invariant at the first emergence, and declined by degree at the second emergence.

Abstract: Terminal phenolic hydroxyl triazine dendrimer (HTHP) was prepared by putting cyanuryl chloride and 1,3,5-benzenetriol into acetone and then adding K₂CO₃ into the mixture as deacid reagent, which is called “One Step Process”. HTHP can be used in the leather tanning process as an additive. The result shows that adding HTHP into leather tanning process can improve the combination tanning property of leather collagen. When we add 10% (based on the mass of pickled skin) of HTHP, the shrinkage temperature of crust is 63.11°C and the mechanism of tanning is same as the vegetable tannin which has abundant of plant polyphenol. When the usage of HTHP is 10% and the aluminum salts is 2.5% (consider the mass of Al₂O₃), the shrinkage temperature of crust can reach to 82.2°C. It can be concluded that it shows synergism when there are both HTHP and aluminum salts in the process.

Abstract: In this paper, the influence of pulsed current annealing on giant magneto-impedance (GMI) effect of Co_66.3Fe_3.7Si₁₂B₁₈ amorphous ribbon under different driving current is studied. The experiment results show that the GMI effect is closely related to the annealing current density. With the increase of annealing current density, the GMI ratio ΔZ/Z rises firstly and the maximal GMI ratio of 53.8% is obtained for the sample annealed at 104A/mm². When annealing current density increases further, the GMI ratio begins to decrease. The mechanism of the pulsed current annealing affecting the GMI effect is explained qualitatively. This paper also discusses the influence of transverse anisotropy field HK induced by annealing on GMI effect. Proper transverse anisotropy field benefits the enhancement of the maximal GMI ratio, however, the GMI ratio will begin to fall as soon as exceeding the critical value.

Abstract: X zeolite behaves excellent properties of shape selective catalysis, molecular sieves and iron-exchange for its unique tunnel structure and large specific surface area. In this paper magnetic core has been introduced into the zeolite structure and magnetic zeolite with high stability and adsorption properties have been prepared. Synthesis conditions and adsorption of Pb²⁺ also have been studied. Magnetic zeolite composite was hydrothermally synthesized with a traditional hydrothermal method by adding magnetic Fe₃O₄ suspension in the zeolite synthesis system. Synthesis conditions and adsorption of Pb²⁺ also have been studied. The products were characterized with X Ray diffraction (XRD), IR spectrometer (IR), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Thermogravimetric (TGA) and differential scanning calorimetry (DSC) instruments. The results show that the products have an X zeolite crystal structure and present super paramagnetic properties. The saturation magnetization value of the product is about 3.7 emu•g^-1. The weight ratio of magnetic Fe₃O₄ in the magnetic zeolite composite is calculated to be about 5%. The magnetic zeolite composites have high surface area and the absorption capability of the products is 196.8mg/g.

Abstract: In this study, melting method is adopted for the preparation of phase change material based EVA /binary fatty acids composite. Phase change temperature and latent heat of the binary fatty acids and EVA /binary fatty acids composite are characterized using Differential Scanning Calorimetry (DSC). The structure and thermal insulation properties of the binary fatty acids and EVA /binary fatty acids composite are investigated using Fourier transformation infrared spectroscope (FTIR) and temperature-recording instrument. The DSC results show that Phase change temperature and latent heat of the binary fatty acids are less than that of pure Stearic Acid and Lauric Acid, The latent heat of EVA /binary fatty acids composite are increase with the increasing of the binary fatty acid content. Cooling curves show that the binary fatty acid and EVA /binary fatty acids composite have good insulation properties. The FTIR results show that EVA and binary fatty acid are combined by intermolecular forces.

Abstract: Silk fibroin film, which has good biological compatibility, is suitable for use as biomaterials and medical materials. However, silk fibroin film in dry state is too brittle to be used by itself. Blending with other natural or synthetic polymers could improve the poor mechanical properties of silk fibroin film. In this paper, recent researches in blend film of silk fibroin and their application were summarized.

Abstract: Three-dimensional needle carbon fibre reinforced carbon and silicon carbide dual matrix composite (C/C-SiC) was a new type of high performance brake materials, and exhibited a series of outstanding advantages such as low density, good echanical properties, especially excellent toughness, to avoid catastrophic brittle fracture. In the present study, the C/C-SiC composites were fabricated by the combination of chemical vapor infiltration with liquid silicon infiltration. The preform was prepared by three dimension needling method. The preform was densified by chemical vapor infiltration to form porous carbon/carbon (C/C) composites. Then, the porous C/C composites were converted into C/C-SiC during LSI, in which silicon carbide matrix was formed by the reaction of carbon and melt silicon. The microstructure and mechanical properties of C/C-SiC has been investigated. The results indicated that the composites were composed of 55 wt%C, 39 wt%SiC and 6 wt%Si. The density of C/C-SiC was 2.2 g•cm^-3 and the open porosity was 6.4%, respectively. The C/C-SiC exhibited good echanical properties, especially excellent toughness, to avoid catastrophic brittle fracture. The flexural and compressive strength can reach to 214.6 MPa and 271.0 MPa, respectively. C/C-SiC had excellent impact damage tolerance of 25.2 kJ•m^-2.