In-Situ and Real-Time Analysis of the Formation of Strains and Microstructure Defects during Solidification of Al-3.5 Wt Pct Ni Alloys
In-Situ and Real-Time Analysis of the Formation of Strains and Microstructure Defects during Solidification of Al-3.5 Wt Pct Ni Alloys
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DOI：
10.1007/s11661-007-9449-2
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发表时间：
2008-02
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影响因子：
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通讯作者：
G. Reinhart;A. Buffet;H. Nguyen-Thi;B. Billia;H. Jung;N. Mangelinck-Noël;N. Bergeon;Thomas Schenk-Thomas
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文献类型：
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作者：
G. Reinhart;A. Buffet;H. Nguyen-Thi;B. Billia;H. Jung;N. Mangelinck-Noël;N. Bergeon;Thomas Schenk-Thomas
通过使用欧洲同步辐射设施 (ESRF) 开发的独特实验装置，结合同步辐射 X 射线照相术和形貌术，对合金凝固进行了原位实时研究。虽然同步加速器 X 射线照相可以研究金属合金的固液界面，但白束同步加速器 X 射线形貌可以研究生长的固体微观结构中应变的形成和缺陷的形成。在本文中，我们介绍了使用 Al-3.5 wt pct Ni 样品进行定向凝固实验时获得的结果。首先，表征热稳定后的初始状态。接下来，深入研究界面形态的不稳定性和向柱状生长状态的转变。形貌观察表明，在微观结构发展过程中，每个枝晶的几个部分会变得混乱。定向障碍被量化，熔点处的铝屈服应力根据辅助臂的弯曲来估计。最后，共晶和枝晶的耦合生长随着共晶相的形成而稳定下来。共晶晶粒变得应变，并且枝晶同时承受额外的应力。
Alloy solidification was investigatedin situand real time by using a unique experimental setup developed at the European Synchrotron Radiation Facility (ESRF) combining both synchrotron X-ray radiography and topography. Although synchrotron X-ray radiography enables the investigation of the solid-liquid interface of metallic alloys, white-beam synchrotron X-ray topography enables the investigation of the formation of strains and defects formation in the growing solid microstructure. In this article, we present results obtained during directional solidification experiments performed with Al-3.5 wt pct Ni samples. First, the initial state after thermal stabilization is characterized. Next, the interface morphological instability and the transition to the columnar growth regime are thoroughly investigated. Topography observation shows that several parts of each dendrite become disoriented while the microstructure is developing. Disorientations are quantified and the aluminum yield stress at the melting point is estimated from the bending of secondary arms. Last, coupled growth of eutectic and dendrites settles with the formation of the eutectic phase. The eutectic grains grow strained and the dendrites concomitantly undergo additional stress.