Applied Mechanics and Materials Vols. 236-237

Abstract: The effects of the rotating electromagnetic field (REF) on the corrosion behavior of the CuNi10Fe1Mn alloy tube billets were investigated by immersion test and electrochemical measurements. It is found that the imposing REF can be used to improve the resulting microstructures which affect the corrosion behavior of the CuNi10Fe1Mn alloy tube billet. The REF could induce the microstructure changes of the CuNi10Fe1Mn alloy tube billets and result in the gains refinement and the preferred orientation on the crystal plane. The improvement of the corrosion behavior is contributed to the change of microstructures of BFe10-1-1 alloy tube billets. The electrochemical measurements and immersion test show that the CuNi10Fe1Mn alloy tube billets with REF increase the corrosion resistance compared with the CuNi10Fe1Mn alloy tube billets without REF. Therefore all these observations suggested a nobler corrosion behavior of the CuNi10Fe1Mn alloy tube billets with the REF.

Abstract: YAG:Ce phosphors were synthesized by co-precipitation method. The photoluminescence intensity of samples sintered by the two-step route increases by about 10%, and with 0.5 wt.% NH4Cl added as flux, surface morphologies and size distribution are improved. The white LEDs were fabricated using as-obtained phosphors. It shows natural white light with chromaticity coordinates of (0.3083, 0.3163), color temperature (Tc) of 6886 K, the average CRI of 75, and the luminous efficacy of 85 ml/W. Therefore, The as-obtained YAG:Ce phosphors could be regard to have potential application in white LED devices.

Abstract: A finite element modeling method based on industrial computed tomography (ICT) technique is proposed to address the insufficient accuracy of traditional grinding method for the meso-structure analysis of composite materials. In this method, the slice images of 3D composites are first acquired by ICT technique. And then, the internal meso-structure images of composite materials are obtained through the digital image processing to the slice images. Finally the meso-structure images are converted to vector format and inputted ANSYS to build the finite element model for the analysis of the mechanical properties. The experimental results show that this method can establish the finite element model and reveal the internal structure and the inherent mechanical properties of composite materials. These researches provide a reference for the manufacture processing of 3D braided composites, and the theoretical basis for the optimal design and performance evaluation. It would be of significance for the improvement of the composites mechanical properties.

Abstract: Propylmethyl cellulose monoester of maleic acid (MAPMC) was synthesized with Propylmethyl cellulose and Maleic anhydride. A modified polyether-type superplastizer (PES) was prepared from ally polyoxyethylenether, Maleic anhydride, acrylic acid and MAPMC through a free radical polymerization. MAPMC and PES were recorded by FTIR. The fluidity of cement paste were investigated, the hydration process of cement for PES were characterized via Hydration Heat Tester. The results indicate that PES superplastizers can improve the fluidity of mortars and more capable of preventing slump loss, the hydroxy group of PES has no negative impact on cement hydration .

Abstract: Inconel 718 and Waspaloy superalloy was vacuum brazed using BNi2 filler. The effect of joint clearance and brazing temperature on the interfacial microstructure, element and microhardness distribution were studied systematically. The microstructure of the brazed joints is both mainly solid solution when the brazing clearance is 30μm at 1080 °C and 100μm at 1140 °C. The results show that the elements diffusion of nickel based filler is more active with the decrease of the joint clearance and increase of brazing temperature. The peak of microhardness is shown at the centerline of brazing seam.

Abstract: It is analyzed that the mechanisms of nano-particles impact on melting temperature, wet ability, and mechanical properties of electronic solders, based on the characteristics of nano-particles, the crystal lattice structure and the interaction between particles and the matrix. The results indicates that if the interface between nano-particles and the matrix is low-energy state, it increases melting temperature of composite solders on ignoring the dissolution of nano-particles, conversely, the high-energy state reduces it. When nano-particles form appropriate frame structure in the liquid solder, the emergence of capillary adsorption can enhance the wettability, the strengthening mechanisms of nano-particles on solder include the Phase II enhancement, grain boundary strengthening and solid-solution strengthening. During the brazing process, nano-particles hinder the diffusion of atoms and reduce the dissolution rate of base materials in liquid solders, to inhibit the growth of the intermetallic compounds (IMC) of interface, thereby enhancing the strength and reliability of joints.

Abstract: Diatomite and glass fiber are used for modifying asphalt concrete in this paper. Besides, wet and dry processes are adopted to achieve the composite modified asphalt concrete. Meanwhile, experimental investigation has been done on its fatigue properties and dynamic mechanical property, it indicates that diatomite-glass fiber modified asphalt concrete has a better capacity to resist fatigue damage. Compared with matrix asphalt concrete, the modified asphalt concrete has higher fatigue life. Thus, its mechanical parameter of fatigue property changes obviously so as to provide a reference basis for the durability design of pavement materials.

Abstract: Ferrofluid is usually used as an inductive core in leaning measurement sensor because it is provided with both liquidity and magnetism. This paper presents a ferrofluid based leaning sensor, detecting small inclination angles against horizontal plane. An approach of numerical simulation for simulating output characteristic of this kind sensor is proposed. From the result of simulation, it shows, after structural parameters are decided, output voltage signal is linear with pumping frequency which appropriate span is 500Hz～2kHz while output voltage signal is linear with leaning angle.

Abstract: Adhesively bonding technology is used increasingly by the automotive and aerospace industries. The design of reverse-bent joint is effective way for improving the bonded joint performance. The influence of preformed angle on the stress distribution of the adhesive-adherend interface is studied in this paper using finite element analysis (FEA). By comparing the results of the FEA for reverse-bent joints with different preformed angle, it can be seen that the preformed angle not only have significant influence on the stress distribution of overlap section, but also changes stress concentration at the spew fillet of bonded joint. The results also indicate that there is a best value of preformed angle in which the reverse-bent bonded joint has the best performance.