Abstract The 2024 aluminum alloy ingot with a diameter of 300 mm was prepared by a direct-chill (DC) cast with the application of a high-shear unit in the sump to study the influence of the intensive melt shearing on the 2024 aluminum alloy. During the DC casting process, the head of the high-shear unit was set to different positions in the sump and the corresponding temperature curves were recorded to further study the role of the position of the high shear unit in the DC casting process with the influence of the intensive melt shearing. The experimental results showed that the intensive melt shearing during the DC casting process results in uniform temperature distribution in the sump, significant grain refinement and reduction of negative centerline macrosegregation. The average grain size in the center of the ingot was reduced from 739.7 μm to 193.8 μm, and the negative centerline macrosegregation of Cu element was reduced from -0.094 to -0.041. It was also found that the shear position plays a significant role in uniforming temperature field, eliminating melt superheating and refining grains. When the high shear position lowered to slurry region, the morphology of grain in the center of the ingot transformed from equiaxed dendritic into finer globular equiaxed grain. The reduction of negative centerline macrosegregation is believed to be due to the forced convection caused by the intensive melt shearing and consequently refined microstructure and uniform distribution of floating grains through the whole section of the ingot.

中文翻译：

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高剪切作用下直冷铸造2024铝合金不同剪切位置的研究

摘要 采用直冷（DC）铸造工艺制备直径为300 mm的2024铝合金锭，并在贮槽中应用高剪切装置，研究了强烈熔体剪切对2024铝合金的影响。在直流浇铸过程中，将高剪切机组的头部设置在贮槽中的不同位置，并记录相应的温度曲线，以进一步研究高剪切机组的位置在直流浇铸过程中的作用与影响强烈的熔体剪切。实验结果表明，在直流铸造过程中，强烈的熔体剪切导致贮槽内温度分布均匀，晶粒显着细化，并减少了负中心线宏观偏析。铸锭中心的平均晶粒尺寸从 739 减小。7 μm 到 193.8 μm，Cu 元素的负中心线宏观偏析从 -0.094 降低到 -0.041。还发现剪切位置在均匀温度场、消除熔体过热和细化晶粒方面起着重要作用。当高剪切位置降低到浆液区时，铸锭中心晶粒的形貌由等轴枝晶转变为更细的球状等轴晶。负中心线宏观偏析的减少被认为是由于强烈的熔体剪切引起的强制对流，从而细化了微观结构和整个铸锭截面上的浮动晶粒均匀分布。还发现剪切位置在均匀温度场、消除熔体过热和细化晶粒方面起着重要作用。当高剪切位置降低到浆液区时，铸锭中心晶粒的形貌由等轴枝晶转变为更细的球状等轴晶。负中心线宏观偏析的减少被认为是由于强烈的熔体剪切引起的强制对流，从而细化了微观结构和整个铸锭截面上的浮动晶粒均匀分布。还发现剪切位置在均匀温度场、消除熔体过热和细化晶粒方面起着重要作用。当高剪切位置降低到浆液区时，铸锭中心晶粒的形貌由等轴枝晶转变为更细的球状等轴晶。负中心线宏观偏析的减少被认为是由于强烈的熔体剪切引起的强制对流，从而细化了微观结构和整个铸锭截面上的浮动晶粒均匀分布。铸锭中心晶粒的形态由等轴枝晶转变为更细的球状等轴晶。负中心线宏观偏析的减少被认为是由于强烈的熔体剪切引起的强制对流，从而细化了微观结构和整个铸锭截面上的浮动晶粒均匀分布。铸锭中心晶粒的形态由等轴枝晶转变为更细的球状等轴晶。负中心线宏观偏析的减少被认为是由于强烈的熔体剪切引起的强制对流，从而细化了微观结构和整个铸锭截面上的浮动晶粒均匀分布。