论文标题
锁定的共晶菌落的生长和形式的伪4D观点
Pseudo-4D view of the growth and form of locked eutectic colonies
论文作者
论文摘要
我们研究了Al-Al2CU作为模型系统的凝固，以了解共晶菌落中模式的出现（例如层状，杆和迷宫样）。为了揭示现场和3D的形态过渡，我们在这里介绍了一种新的基于同步加速器的X射线成像过程。我们的方法同时使时间上（200毫秒）和空间分辨率（$ 0.69^2μm^2/Pixel $）在传统成像方法上。从此过程中获得的大量信息使我们能够在炎热对流的存在下可视化晶体上的“锁定”共晶微观结构的发展。该数据直接洞悉了羊膜到杆转变的机理，因为共晶可容纳界面组成和生长速度的波动。我们发现，这种转变是由作用于固体液体式三连的杂质驱动力来引起的，该力必须克服固体接口的刚度。我们的伪4D成像策略对固化科学界具有广泛的吸引力，因为它可以克服常规的原位X射线显微图像学的时空权衡。
We investigate solidification of an Al-Al2Cu as a model system to understand the emergence of patterns (such as lamellar, rod and maze-like) within eutectic colonies. To uncover the morphological transitions in-situ and in 3D, we introduce here a new synchrotron-based, X-ray imaging procedure. Our method simultaneously maximizes the temporal (200 ms) and spatial resolution ($0.69^2 μm^2/pixel$) over that of traditional imaging approaches. The wealth of information obtained from this procedure enables us to visualize the development of a crystallographically `locked' eutectic microstructure in the presence of thermosolutal convection. This data provides direct insight into the mechanism of the lamella-to-rod transition as the eutectic accommodates fluctuations in interfacial composition and growth velocity. We find that this transition is brought about by impurity-driven forces acting on the solid-solid-liquid trijunction that must overcome the stiffness of the solid-solid interfaces. Our pseudo-4D imaging strategy holds broad appeal to the solidification science community, as it can overcome the space-time trade-off in conventional in situ X-ray microtomography.
