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利用X射线同步辐射影像技术对Al-15%Cu(质量分数)合金凝固过程的枝晶生长和破碎现象进行了实时观察.通过加入脉冲电磁场和改变枝晶生长方向获得了大量不同实验条件下的动态影像.利用Matlab软件对实验结果进行定量化分析,开发了统计测量程序,统计了枝晶破碎数量随不同实验条件的变化,测量了枝晶破碎数量沿糊状区深度、糊状区固相率的分布关系.结果表明,加入电磁场、逆重力方向生长和生长速度快的枝晶会产生更多的枝晶破碎;枝晶破碎数量沿着糊状区深度、糊状区固相率呈一定的Gauss分布,且在固相率为0.45左右达到峰值.最后分析了速度场造成的缩颈断裂、重力场造成的溶质富积以及电磁场造成的晶间对流对上述定量化结果的影响程度.
The phenomenon of dendritic growth and fragmentation in Al-15% Cu alloy during solidification was observed by using X-ray synchrotron radiation imaging technology. A large number of different experimental conditions were obtained by adding pulsed electromagnetic field and changing the growth direction of dendrite Dynamic image.The experimental results were quantitatively analyzed by Matlab software, a statistical measurement program was developed, the number of dendrite breakage was calculated with the change of different experimental conditions, the number of dendrite breakage along the depth of paste area, The results showed that the dendrites were more dendritic when demagnetizing in the direction of gravity and growing fast in the direction of gravity, Gaussian distribution, and reaches the peak value at the solid fraction of 0.45. Finally, the influence of the necking and fracture caused by the velocity field, the solute accumulation caused by the gravitational field and the intercrystal convection caused by the electromagnetic field on the quantitative results are analyzed.