Advanced Materials Research Vols. 765-767

Abstract: In this paper, the deformation properties of AZ31+Sr+Y magnesium alloy sheets produced by twin-roll casting (TRC) and sequential hot rolling were studied by the tensile testing at a strain rate of 7×10^-4s^-1 and various temperatures: room temperature (RT), 200°C, 300°C and 400°C, respectively. The result shows that the microstructure of AZ31+Sr+Y alloy was refined obviously by adding elements Sr and Y, the elongation of the alloy increased with increasing temperature, and the fracture behavior of the alloy changed from brittle fracture to ductile fracture with increasing temperature. During the process of plastic deformation of AZ31+Sr+Y alloy, the twin plays a leading role at room temperature; the dislocation movement is regarded as the main deformation mechanism at 200° C; at the higher temperature (above 300°C) the grain boundary slip (GBS) plays a dominant role .

Abstract: t is very important to produce coupler steel castings with low oxygen content and the exact aluminum residuals. Low and inconsistent aluminum elemental recovery problems are often encountered when adding aluminum strips or lumps into the baths of 25MnCrNiMo steel. This is the case because aluminum presents some of the following characteristics: low melting point, lower density much more than the molten steel, low solubility in the liquid steel, high affinity due to oxygen. These circumstances lead to difficulties or risks, such as: poor or erratic recovery of alloying aluminum element, oxygen content in casting out of range, violent and dangerous splashing. To counter these problems existed in conventional method, aluminum wire injection process was introduced in this work, and the effects of aluminum wire feeding are investigated. The results show when using the aluminum wire injection, stable cleaner steel melt is obtained, i.e. oxygen content and the aluminum residuals are under control accurately, and what's more, the recovery of the aluminum is 95%. The treatment time was about 1 minute, and the melting period was shortened. Favorable metallurgical achievements and economical benefits were gained.

Abstract: The green environmental Li-ion power battery becomes the research heat spot of new energy technique and gets people's more and more attentions. This article overviews the process of coating technique of the Li-ion power battery, and the drying technique of Li-ion power battery electrode has a great influence on the Li-ion power battery performance. After analyzing the principle and merits and demerits of various dry methods of Li-ion power battery electrode, the project decides to apply hot-wind of circulating and shock drying method to dry Li-ion power battery electrode. The method has already successfully applied to practice production and has obtained a good economic efficiency for enterprise.

Abstract: Li-ion power battery is one of the key technology for electric vehicle and the most important technology for the producing the Li-ion power battery is coating. At present, the ways of Li-ion power battery coating mainly are the roller coating and the slot extrusion coating. As the roller coating technology is the proven technique and the equipment is simpler, it is a better choice. The key technology of the roller coating is ensuring thickness uniformity and accuracy of the battery electrode. According to the production sample data analysis of the roller coating device, the coating machine we developed successfully achieved the required technical indicators.

Abstract: This paper presented the abrasive wear process of a particle pressing into the material and sliding on the surface simulated by finite element method to reveal wear characteristics and effect factors. The contact stress and surface deformation of material were indicated and material wear resistance was studied, it was found that the stress and the deformation of subsurface not only depends on mechanical properties of material and original surface shape, but also on deformed surface profile due to sliding. In order to prove the effects of material yield stress and deformation harden property on surface deformation and abrasion resistance property, the abrasive wear of three kinds of carbon steel were taken for examples, the simulation results were presented that the larger yield stress of carbon steel, the less surface deformation and the better abrasion resistance property when a particle sliding on the surface. The simulation results also shown that the deformation harden of carbon steel could reduce surface deformation, but couldnt always improve abrasion resistance property.

Abstract: Particulate reinforced titanium matrix composites (PTMCs) are attracting increasingly attention in various engineering applications. In this paper, comparative grinding experiments of PTMCs were carried out using WA abrasive wheel and CBN abrasive wheel. The morphology of the ground surface was observed by scanning electron microscope. The main results are summarized as follows: (1) The damage of reinforcements in the PTMCs results from the plowing and shearing during grinding in the form of crater, micron gap, broken, coating and micron crack. (2) The formation of grinding chip is a function of the collaborate removal of reinforcements and matrix material. (3) The surface fracture pattern of PTMCs using WA wheel is to form the grinding chip through severe extrusion. While using CBN wheel, the abrasion due to the formation of the wear debris is the main surface fracture pattern of PTMCs.

Abstract: It was simulated with rigid viscoplastic finite element theory for fan-shaped profile extrusion process of AZ31 magnesium alloy, and analyzed the distortion mesh of the various stages of the extrusion process and obtained the speed field, stress field and strain field in inner workpiece during the deformation course. Appiying to orthogonal experimental method, we carried out nine simulations with the different extrusion ratio, extrusion temperature and extrusion speed. The above three main factors impacted the organization of the extrusion products, designed into three levels respectively. It was used the mean-square deviation of effective stress at the die orifice during the extrusion forming to determine the best technical parameters. With the best technical parameters and normal technical parameters obtained above, we had a extrusion test and observed the microstructure of extrusion products.

Abstract: By the method of experiment and simulation of numerical value, destructive effect of SFRC under strong impact load is studied, the destructive effect of numerical value simulation is well matched with the experimental result, it is analyzed that the destructive effect of SFRC explosion is affected by the main factor of the content of steel fiber in SFRC, and effects not only on the destructive parameter of SFRC, but also on its form and compress destructive coefficient K_a.

Abstract: Computer aided mass assessment technology could be given consideration to both efficiency and fair, and could be finished large scale house assessment with low cost and high efficiency in short time. But, there are some difficulties in mass assessment technology in collecting house tax in China and it is difficult for people to carry it out. The article discusses the difficulties in establishing mass assessment mode in collecting house tax in China and puts forward some countermeasures.

Abstract: In distribution market, because there are a lot of uncertainty factors such as price and load, so it is a big problem to balance benefit and risk for generation and distribution companies. Since they are both inclined to avoid the market risk, in order to make the most profit for both companies, a purchase and sell model in distribution market based on contract is proposed in this paper. And a power repurchase term is added in the contract to avoid the risk incurred by load fluctuation. Using CVaR(conditional risk at value) as the risk measuring criterion, a two-layer schedule model is set up to simulate the sale and purchase behaviors of generation and distribution companies. And the optimal power sale price for generation company and optimal power purchase quantity for distribution company are calculated by this model. As the case shows, by setting the different risk level, their market characteristics and relationship also change but always follow the risk avoiding rule. So the model can reduce the risk in distribution market for both companies under certain conditions.