Applied Mechanics and Materials Vols. 488-489

Abstract: In this research, a series of [Fe₈₀Ni₂₀-O/NiZn-ferrit_n multilayer thin films with different insulation layer thickness were prepared by magnetron sputtering at room temperature. The high frequency soft magnetic properties of [Fe₈₀Ni₂₀-O/NiZn-ferrit_n multilayer thin films were investigated. It was found that the in-plane magnetic anisotropy field (H_k) and saturation magnetizations (4πM_s) can be adjusted by changing the insulation layer thickness, and the optimal H_k and 4πM_s can be obtained as the insulation layer thickness of 2.5 nm. The adjustment of insulation layer thickness is essential to obtain low coercivity (H_c) and high permeability (μ) of the multilayer thin films. The measured resistivity (ρ) of [Fe₈₀Ni₂₀-O/NiZn-ferrit_n multilayer thin films was increased from 211 to 448 μΩcm with increasing the insulation layer thickness.

Abstract: As we know that ceria (CeO₂), alumina (Al₂O₃), aluminum (Al) and iron oxide (Fe₂O₃) can improve the anti-aging properties of the rubber, mixed these materials with carbon black and filling conductive silicone rubber, some samples have been prepared. Have described the anti-aging method of the silicone rubber and discussed the test method of the changes in properties after aging. Have tested the changes of mechanical properties and electrical conductivity before and after the air aging test of the conductive silicone rubber which with or without addition of modified material. Have discussed the reasons why modified materials can improve the anti-aging performance of the conductive silicon rubber. The results show that with the addition of these types of nanomaterials the stability of mechanical and electrical properties of the conductive silicone rubber can be improved before or after aging treatment.

Abstract: Three groups of strain gauges were embedded in the epoxy adhesive coating deposited on the steel substrate with different depths. The transverse and longitudinal strains during the curing process were tested. It was found that the transverse and longitudinal strains decreased remarkably when the curing time was lower 24h. At a longer curing time, the strains almost kept steady. In addition, the more close to the surface of epoxy adhesive coating, the higher the strains were. The solidification contraction stress in the epoxy adhesive coating during the curing process were also estimated, and the attempts were made to relate them to the restrained contraction of the epoxy adhesive coating.

Abstract: The deposition behavior of Al-Si particle on magnesium alloy by supersonic particles deposition was investigated by numerical stimulation. The results demonstrated that critical velocity of sprayed particle reduced as its initial temperature increased; Temperature at interface increased rapidly and reached to the value higher than melting point of Al-Si particle and ZM5 magnesium substrate, which predicts the melting possibility for collision interface. Morphology and microstructure of Al-Si coating on magnesium alloy were analyzed by SEM and TEM. The results indicated that there existed large amount of nano/micro-scale grains produced by sputtering and impacting of the melting Al-Si jet. And obvious interface belt had been formed at brim of the deposited particles, nanocrystalline phase region generated by rapid solidification of melting Al-Si particles, justified the occurrence of interface melting phenomena.

Abstract: The photo-induced fluorescence enhancement for a BOPIM derivate, which was found weak or no fluorescence in solvents due to twisted intramolecular charge transfer (TICT) was investigated. The quenching process because of TICT state is substantially removed and fluorescence emission intensity increased remarkably, induced by UV-irradiation. This phenomenon could only found in moderate polar solvent, such as CHCl₃, THF and 1, 4-dioxane (DIOX), but not in more polarity solvent, such as CH3CN, CH3OH. It is indicated that the transformation from TICT to ICT state take place easily in moderate polar solvents.

Abstract: The microstructure and mechanical properties of as-cast Mg-5Y-(2, 3, 4)Sm-0.8Ca (wt.%) alloys have been investigated. The results show that the microstructure of as-cast alloys consists of α-Mg matrix, Mg₂₄Y₅, Mg₄₁Sm₅ and Mg₂Ca. With the increase of Sm addition, the tensile strength increases at first, and then decreases. Mg-5Y-3Sm-0.8Ca alloy has the highest strength and can be a basis for developing light structural materials.

Abstract: The composite coating with TiC-TiB₂-Ni₃Al was fabricated on 45 steel by laser cladding. The microstructure and high temperature oxidation resistance of coating were investigated. The results show that, the main phases of coating are α-Fe, TiC, TiB₂, Ni₃Al, (Fe,Cr)₇C₃ and Al₂O₃. The interface of coating and substrate material is metallurgical bond; the coating is uniform and dense without cracks and pores. The fine particles of TiC and TiB₂ disperse uniformly in the coating. After oxidized at 1000°C for 60 h, the oxidation film is consisted of spherical oxides of Al, Ti and Cr, they can hinder the diffusion between oxygen and metal atoms and make the coating possess outstanding high temperature oxidation resistance.

Abstract: The microstructure and mechanical properties of Mg-9Gd-2Y-1Sm-0.5Zr alloy have been studied by micro-analysis and tensile tests. The results showed that the alloy mainly consists of α-Mg matrix, Mg₅Gd and Mg₂₄Y₅. With the increase of temperature, the tensile strength of the alloy increases at first and then decreases, and the peak appears at 250°C.

Abstract: The flow of syndiotactic 1,2-polybutadiene (s-PB) filled with carbon nanotubes (CNTs) nanocomposites behave quite differently from Newtonian fluid, they exhibit both viscous and elastic characteristic and are termed as viscoelastic fluid. The viscoelastic properties can be determined by a Rheometer. In this studies a parallel plates arrangement where the upper plate is being rotated/oscillated with a sine wave and the stress and phase angles were measured. From our study on syndiotactic 1,2-polybutadiene and its nanocomposites with carbon nanotubes (CNTs), the results show that for a fixed amplitude and temperature, the storage and loss modulus increase with the increase of frequency. At low frequency the s-PB/ CNTs nanocomposites melts behaved more like a viscous liquid and changed the behavior into more elastic at high frequency.

Abstract: In order to effectively improve the calculation accuracy of finishing rolling force model for hot rolling wide and heavy stainless steel clad sheets, based on the E.Orowan unit pressure equilibrium differential equations and R.B.Sims unit pressure formulas, this paper divides hot-rolled composite deformation area into I, II two zones according to rolling stock jamming experiment, and then derives the finishing rolling force calculation formulas. Finally, by ANSYS/LS-DYNA thermal mechanical coupling simulation and experiment, the results show that compared with measured values, the relative error of simulated values is about 20%, the relative error of calculated values is less than 10%. Therefore, the rolling force model can accurately predict the size of rolling force and effectively improve the calculation accuracy of rolling force.