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| 1 | Numerical simulation of solidification of liquid aluminum alloy flowing on cooling slope显示文摘Preparation of semisolid slurry using a cooling slope is increasingly becoming popular,primarily because of the simplicity in design and ease control of the process.In this process,liquid alloy is poured down an inclined surface which is cooled from underneath.The cooling enables partial solidification and the incline provides the necessary shear for producing semisolid slurry.However,the final microstructure of the ingot depends on several process parameters such as cooling rate,incline angle of the cooling slope,length of the slope and initial melt superheat.In this work,a CFD model using volume of fluid(VOF) method for simulating flow along the cooling slope was presented.Equations for conservation of mass,momentum,energy and species were solved to predict hydrodynamic and thermal behavior,in addition to predicting solid fraction distribution and macrosegregation.Solidification was modeled using an enthalpy approach and a volume averaged technique for the different phases.The mushy region was modeled as a multi-layered porous medium consisting of fixed columnar dendrites and mobile equiaxed/fragmented grains.The alloy chosen for the study was aluminum alloy A356,for which adequate experimental data were available in the literature.The effects of two key process parameters,namely the slope angle and the pouring temperature,on temperature distribution,velocity distribution and macrosegregation were also studied. | N.K.KUND P.DUTTA | 2010 | 中国有色金属学会会刊:英文版2010，20，S3： | 1 |
| 2 | 板面长度和冷却速度对A356合金斜板凝固过程与显微组织的影响(英文)显示文摘当A356合金流经由底部反向水流冷却的斜板时将发生部分凝固。在板面上将连续形成柱状枝晶。由于强制对流作用,这些枝晶将被剪切成等轴晶并被出口的半固态浆体冲刷。板面冷却速度可为高质量半固态浆体提供需要的凝固过程,而板面长度可提供必需的剪切过程。将半固态浆体在金属模具中冷却以制备具有理想微观组织的半固态锭坯。此外,对半固态铸造锭坯进行热处理以提高表面质量,并对半固态铸造和热处理后锭坯的微观组织进行对比。研究板面长度和板面冷却速度对斜板冷却锭坯凝固过程和显微组织的影响。三种板面长度(200,250,300 mm)分别对应不同传热系数(1000,2000和2500 W/(m2K))。最佳板面长度和相应的传热系数分别为250 mm和2000 W/(m2K),在此条件下,由于没有浆体附着在板面上,锭坯具有细小的球状组织。 | N.K.KUND | 2015 | Transactions of Nonferrous Metals Society of China2015，25，1： | 1 |
| 3 | 熔体浇注温度和板倾斜度对倾斜板制备A356铝合金的凝固和显微组织的影响(英文)显示文摘采用倾斜板制备A356铝合金半固态浆料。通过倾斜板底部的逆流水冷却使A356合金熔体在流下倾斜板时发生局部凝固,从而导致在板壁上形成连续柱状枝晶。由于强制对流作用,这些树枝晶被折断成等轴和破碎的晶粒,然后被连续冲洗而在斜板出口形成半固态浆料。熔体浇注温度是影响凝固组织的重要条件,而倾斜度为优质半固态浆料提供必要的剪切作用。将得到的浆料在金属模具中凝固以制备理想显微组织的半固态铸造坯料。然后,通过热处理以提高半固态铸造坯料的表面质量。对半固态铸造和热处理后坯料的显微组织进行分析。研究熔体浇注温度(620,625,630和635°C)和板倾斜度(30°,45°,60°和75°)对斜板制备A356铝合金的凝固和显微组织的影响。结果表明:在625°C的熔体浇注温度和60°斜板倾角时,A356铝合金具有细小和球状的晶粒,是最佳的显微组织。 | N.K.KUND | 2014 | Transactions of Nonferrous Metals Society of China2014，24，11： | 0 |
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