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研究了半固态A356铝合金熔体中混沌对流的表征,及电磁场诱发的混沌对流对半固态A356铝合金熔体中初生相形貌演变的影响.通过Fluent软件研究了电磁场作用下A356铝合金熔液中微粒的流动轨迹,计算了这些流动轨迹的Kolmogorov熵和分形维数,证明了施加适当的电流频率能在合金熔体中产生混沌运动.结合实验研究,对不同电流频率及工艺参数的实验结果进行对比.研究结果表明,A356铝合金熔体在650℃浇注,电流频率为30 Hz的电磁场中搅拌15 s,并在590℃保温10 min,此时凝固系统的Kolmogorov熵为6829.5 nat/s,分形维数为2.2439,初生相的平均等积圆直径为59.86 mm,平均形状因子为0.71,此时晶粒最圆整细小,组织形貌最佳.
The effects of chaotic convection induced by electromagnetic field on the morphology of primary phase in semi-solid A356 aluminum alloy melt were studied by means of Fluent software. And the Kolmogorov entropy and fractal dimension of these trajectories are calculated and it is proved that the appropriate current frequency can generate chaos in the alloy melt.According to the experimental study, the experiment of different current frequency and process parameters The results show that when the A356 aluminum alloy melt is poured into a 650 ℃ electric field with a current frequency of 30 Hz and stirred for 15 s at 590 ℃ for 10 min, the Kolmogorov entropy of the solidification system is 6829.5 nat / s , The fractal dimension is 2.2439, the average circle diameter of the primary phase is 59.86 mm, and the average shape factor is 0.71. At this time, the grains are the most complete and fine, and the best is the topography.