Advanced Materials Research Vol. 900

Abstract: Machining accuracy of thin-walled parts is easily affected by clamping and cutting deformation due to its poor stiffness. In this paper, synchronous optimization method of clamping force and cutting parameters is presented based on GA and FEM. The optimization objective is to minimize the maximum deformation and to improve the machining efficiency. GA is used to optimize cutting parameters and clamping force, and FEM is used to predict the machining deformation of the thin-walled workpiece. Finally, taking a titanium alloy thin-walled part with irregular shape as an example, the optimal clamping force and cutting parameters at every cutting position are obtained to demonstrate the feasibility of the method.

Abstract: Microwave crag broken is a thermal assisted rock breaking method which could melt rocks. Microwave assisted rock breaking method will not bring new impact, wear and tear, instead, the microwave pretreatment on the rock reduces the difficulty of breaking rock and prolongs the service life of the drill bit. This microwave generator accumulates the microwave near the hot spot to soften and melt the rock through generating and transmitting the microwave. And we had experimented with the microwave generator to penetrate the wood, and weaken the strength of the rock. And the experiment proved the scheme of the microwave assisted rock breaking through microwave near field energy and the thermal runaway effect is feasible.

Abstract: Electron beam melting (EBM) is a relatively new rapid, additive manufacturing technology which can allow for the fabrication of complex, multi-functional metal or alloy monoliths by CAD-directed, selective melting of precursor powder beds. By altering the beam parameters and scan strategies, powder burn-through phenomena and uneven temperature field can be improved. In this paper the analyses for editable electron beam scanning track are presented based on the influence to the temperature field over the formation zone and the powder burn-through phenomena. The most promising strategy, non-uniform scanning mode for irregular scanning path, is approved by the ANSYS simulation and a two-dimensional scan experiment. The result shows non-uniform scanning mode can improve the uniformity of the temperature field and reduce the powder burn-through phenomena.

Abstract: In this study, 2024 Al alloy and AZ31B Mg alloy were brazing with mechanical stirring. The effects of brazing speed on microstructure and shear strength were investigated. The results show that oxide films on Al base metal surface broken completely at lower brazing speed. The continuous IMCs layer was broken into thinner one and blocky IMCs distribution in filler metal more evenly at lower brazing speed. The shear strength value near Al and Mg interface up to 53.1Mpa and 41.5Mpa respectively.

Abstract: A new automatic RIE etching system has been developed. Multi-layers of magnetic materials were fabricated using this system. We compared the process of using conventional Ar gas plasma and the process using CO/NH₃ gas plasma. Then by combining the two processes, we achieved smooth surface and good uniformity with a good selectivity to photoresist mask. And few of corrosions appeared at the sidewall of trench. Additionally, the etching process could stop exactly at the stop layer. The whole processes ran at a chamber without control of temperature, pressure and end point detection.

Abstract: The temperature distribution of the hot-rolled strip in the ROT cooling process was calculated and analyzed using ABAQUS in this paper. The complicated heat transfer coefficients of hot strip considering the position effects of top and bottom nozzles, and the non-uniform heat transfer situation along the width direction were defined by user subroutine. The simulation results were in good correlation with test results. It’s helpful for further analysis to improve the temperature distribution uniformity and the simulation accuracy for FE model, and guide the on-site production.

Abstract: In the process of integrated circuit design and manufacturing, dummy metal fill can improve the planarity of layout after Chemical Mechanical Polishing (CMP). However, it will also cause lithography distortion and Critical Area (CA) variation. This paper compares and analyzes the influences of lithography distortion due to metal fill on CA from the perspectives of different defect particles based on 45nm technology node. The results indicate that dummy metal fill can increase open CA after lithography and the defect particle with the diameter of 0.066um leads to the largest increment percentage of open CA, which will take up almost 10%. This paper is instructive in researching dummy metal fill and CA or related fields in the future.

Abstract: A phosphate rock containing MgO 7.95% and SiO₂ 9.64% has fine dissemination size, which is from Yichang city in Hubei province, China. Technical conditions of the ore were investigated by performing reverse flotation, which adopted anion collector to flotate magnesium. The results showed that under H₂SO₄ 3500g/t, H₃PO₄ 2500g/t, MG-2 3200g/t, phosphate concentrate with P₂O₅ 31.91%, MgO 0.97% and recovery of 88.71% were obtained by employing the process of close-circuit reverse flotation.

Abstract: The mechanical model of Tube Solid Granules Medium Forming (SGMF) is simplified to three pressure-transfer models: uniform pressure model, unequal diameter model and tube SGMF model. Combining the conclusions of the SGMF investigation and the theories of powder mechanics, lateral pressure-transfer regularity of SGMF under high pressure has been investigated and the mathematical formulas of pressure distribution have been obtained. According to the theoretical analysis, the lateral pressure and the depth of solid granules can be expressed by a segmented function. An experimental set-up has been designed and manufactured to evaluate the theoretical results, good correlation has been observed between the theoretical results and the experimental data.

Abstract: The collophane is in oolitic structure, and associates with the gangue intricately; and hence a good concentrate in performance is hardly produced only by rinsing, in order to achieve a full liberation, fine-grinding is needed for the cellophane. Based on the results of both direct and reverse flotation tests, it shows that reverse flotation is effective in the benefication of the apatite to a certain extent. When reverse flotation is used to dress the run-of-mine which contains 26.95%P₂O₅, a concentrate containing 32.69% P₂O₅ can be obtained at a recovery of 84.99%.