State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an Shaanxi, 710072, China.
Univ. Grenoble Alps, LNCMI, F-38000, Grenoble, France.
Sci Rep. 2017 Jul 10;7(1):4958. doi: 10.1038/s41598-017-05385-y.
High magnetic field is a powerful tool to tune the microstructure and improve the properties of materials. In this report, the nucleation behavior of undercooled CoSn near eutectic alloy under strong homogeneous and gradient magnetic fields have been investigated using glass slag fluxing method in a 12 T superconducting magnet. The mean undercooling of the undercooled melt is not altered by homogeneous magnetic field but depressed by gradient magnetic field. The highest temperature during recalescence is strongly altered by magnetic field, where an enhancement effect is observed under gradient magnetic field and an opposite effect in homogeneous magnetic field. The reason is interpreted by discussion about the magnetic field on the thermodynamics of nucleation and also the purifying effect of the glass slag, the magnetic properties and the magnetic force exerted on the undercooled melt.
强磁场是调控材料微结构和改善性能的有力工具。在本报告中，我们采用玻璃渣助熔法，在 12 T 超导磁体中研究了过共晶 CoSn 合金在强均磁场和梯度磁场下的非平衡晶核形成行为。均磁场不会改变过冷熔体的平均过冷度，但梯度磁场会降低其过冷度。磁场强烈改变再辉过程中的最高温度，在梯度磁场下观察到增强效应，而在均磁场下则观察到相反的效应。通过讨论磁场对形核热力学的影响以及玻璃渣的净化作用、磁性和磁场对过冷熔体的作用力，对其原因进行了解释。
