Frontiers of Manufacturing and Design Science III

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Authors: Long Wei, Zong De Liu, Xin Zhi Li, Ming Ming Yuan, Cheng Yuan Zhong
Abstract: Cr3C2-NiCr has high quality of wear resistant properties and is widely used in abrasive environment. In this paper, Cr3C2-NiCr coating was prepared on 45 steel by laser cladding technology. Analysis and research of the coatings were achieved by SEM and XRD to determine the main component and the different region on coatings. The hardness and the element component were investigated by micro-hardness tester and EDS. Abrasion tests were performed to contrast the wear resistance of two materials. The results indicate that the hardness of the coatings is nearly 3 times as the substrate. The coatings are well combined with the substrate and the phase of Cr3C2 has a large proportion in the coatings. Abrasion tests show that the average of wear rate on substrate is 5.2 times as the coatings.
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Authors: Jie Li, Wei Guang Yang, Wei Min Shi, Ji Rong Li, Lin Jun Wang
Abstract: The as-prepared high-quality Cu2ZnSnS4 nanocrystals were prepared by solvothermal method. The influence of the reaction temperature, growth time and mixed solvent on the structural and composition of the Cu2ZnSnS4 nanocrystals was investigated. XRD result shows the percentage of ethylenediamine in the mixed solvent have an important influence in the synthesis process of pure-phase Cu2ZnSnS4 nanocrystals. EDS result proves the particles belong to Cu rich and Zn poor composition.
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Authors: Zeng Lei Ni, Ai Qin Wang, Jing Pei Xie
Abstract: This paper studied the combined effects of particle size and distribution on the mechanical properties of the SiC particle reinforced Al-30Si alloy composites. The microstructure of experimental material was analyzed by SEM, the tensile strength and physical properties were examined. The results show that, with the increase of the SiC particle size in the composites, the clustering degree of the SiC particles decreases in the matrix, the SiC particles distribute more ununiformly. The tensile strength is influenced by the SiC particle size, the tensile strength of the composite reinforced by 13μm sized SiC particles is the highest.
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Authors: Shu Yan Wu, Ze Sheng Ji, Chun Ying Tian, Ming Zhong Wu
Abstract: This work is to study the influence of heat treatment on microstrudture and mechanical properties of AZ31B magnesium alloy prepared by solid -state recycling. AZ31B magnesium alloy chips were recycled by hot extruding. Three different heat treatments were conducted for recycled alloy. Mechanical properties and microstructure of the recycled specimen and heat treated specimen were investigated. 300°C×2h annealing specimen exhibits finer grain due to static recrystallization, and microstructure of 400°C×2h annealing specimen becomes more coarse. 300°C×2h annealing treatment improves obviously strength and ductility of recycled alloy. Ultimate tensile strength of alloy decreases and elongation to failure increases after 400°C×2h annealing. Grain size, dislocation density and bonding of chips have an effect on the elongation of recycled materials. 190°C×8h ageing has no influence on microstructure and mechanical properties of recycled alloy.
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Authors: Hu Jun Jia, Yin Tang Yang, Lian Jin Zhang, Bao Xing Duan
Abstract: A novel 4H-SiC MESFET with stepped-channel (stepped-spacer) structure is proposed for the first time and analyzed by 2D numerical simulation. Based on the stepped buried oxide structure of SOI which can produce additional electrical Electric field peaks, much more advantages can be obtained through a stepped-channel structure compared to that of the field terminal technology, such as an obvious increase of the breakdown voltage which is equal to the electric field to the path integral, and the lower capacitances lead to a higher cut-off frequency. The simulation results show that a 100% higher saturated drain current and a 153% larger breakdown voltage can be obtained utilizing the stepped-channel structure MESFET than those of the conventional counterpart.
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Authors: Wen Li Zheng, Wei Yang
Abstract: Diluted magnetic semiconductor Zn1-xMnxO crystals were synthesized at 430°C for 24h by hydrothermal method. 3mol·L-1KOH was used as the mineralizer, and the fill factor is 35%. The obtained crystals show a ZnO wurtzite structure, with positive polar faces{0001}, negative polar faces{000 }, p faces{ 011} and –p faces { 01 } exposed. The height of the crystal is 5-30 m and radius-height ratio is2:1. Mn atom concentration of 2. 6% (x=0.026) was determined using X-ray energy dispersive spectroscopy ( EDS). The crystals show low-temperature ferromagnetism with Curie temperature of 50K.
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Authors: Dyi Cheng Chen, Jiun Ru Shiu, Fung Ling Nian, Ming Ren Chen
Abstract: The bicycle is not only a pollution-free method of transportation, but also has sport and recreation functions. Therefore, the bicycle attracted attention in now society gradually. The purpose of this research is mainly to innovative design a forging die of pedal of bicycle for the company’s needs. We first design a die with simulation analysis of bicycle pedal by utilizing a commercial finite element package software during research process. Moreover, a series of simulation analyses with the variables depended on different press velocity of ram, temperature of die and friction factor of the die is performed to evaluate the methods of light quantification in the forging for bicycle pedal. Under various forging conditions, it analyses the curvature distribution and damage distribution of the billet. The optimal parameters to control are obtained with Taguchi methods. Finally, we identified the finite element results for high-strength design suitability of 6061 aluminum alloy bicycle pedal.
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Authors: Wei Yuan Yu, Wen Jiang Lu, Nai Rui Li
Abstract: Al85Ni10Zr3Y2 and Al80Ni10Zr8-xCuxY2(x=1,2,3,5) alloy ribbons had been prepared by single roller melt-spinning process under vacuum conditions. The ribbons were investigated by X–ray diffraction and differential scanning calorimetry (DSC). The results revealed the strong effect of content of Cu、Zr elements on the glass forming ability and the thermal stability of the alloys. The formation of amorphous alloys are sensitive to contens of these two elements. The completely amorphous alloy or the primary amorphous phase alloy can be obtained when the content of Cu or Zr reach an optimization, otherwise only gaining crystal phase. Al80Ni10Zr7Cu1Y2 and Al80Ni10Zr3Cu5Y2 alloys possess the excellent glass forming ability, which can form the completely amorphous alloy or the composite material of the partial crystal in remaining amorphous.
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Authors: Min Li, Li Guang Xiao, Hong Kai Zhao
Abstract: Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The isothermal crystallization of PE/MMT nanocomposites at different MMT concentration (from 0.1 wt % to 1.2 wt %) was investigated by differential scanning calorimetry (DSC). The crystallization kinetics shows that the Avrami exponent of PE/MMT nanocomposites is decreased compared with pure PE, which indicates a decrease in the crystal growth dimension. This is attributed to the stems of PE crystals confined in the MMT layers. The crystallization rates of PE/MMT nanocomposites are faster than those of pure PE. However, when the content of MMT increases from 0.1 wt % to 1.2 wt %, the crystallization rate of PE/MMT nanocomposites is decreased.
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