细化剂对等轴枝晶生长形态和元素微观偏析的影响

Effect of Alloy Refiners on Growth Morphology and Micro-Segregation of Equiaxed Dendrites

在材料微观组织与性能的研究中,对等轴晶形核及生长过程的研究具有重要的科研价值和实用意义。除了通过数学模型进行理论研究,直接的观察极有必要。长期以来,由于高温熔体对可见光不透明,金属的凝固过程一直是一个"黑箱"。X射线同步辐射成像技术的发展使金属凝固过程的动态、连续观察成为可能。作为一种高亮度、高能量的X射线源,同步辐射X光可以穿透数毫米厚的铝熔体并形成清晰影像。近年来,本课题组针对合金凝固过程中的形态演化问题,在上海同步辐射光源开展了持续研究,本文介绍了其中部分研究结果,内容涉及凝固过程中等轴枝晶的形成和长大的动态观察,特别关注形核剂的添加对等轴枝晶生长形态和元素微观偏析的影响。

It has important scientific value and practical significance to investigate nucleation and growth process of equiaxed dendrites. In addition to theoretical study by mathematical model,direct observations are very necessary. For a long time,the solidification process of metals has been a " black box" due to the high temperature melt that is opaque to visible light. The development of X-ray synchrotron radiation imaging technology has made it possible to carry out dynamic and continuous observations of metal solidification. As a high brightness,high energy X-ray source,synchrotron radiation X-ray can penetrate aluminum melt with a thickness of several millimeters and obtain clear images. In recent years,our research group carried out continuous research in the field of alloy solidification morphology evolution in Shanghai synchrotron radiation facility( SSRF). Some research results were reported in this paper,involving dynamic observations of the formation and growth of the equiaxed dendrites. A special attention was paid to the effect of alloy refiners on growth morphology and micro-segregation of equiaxed dendrites.