CHARACTERIZATION OF THREE-DIMENSIONAL DENDRITIC STRUCTURES IN NICKEL-BASE SINGLE CRYSTALS FOR INVESTIGATION OF DEFECT FORMATION
CHARACTERIZATION OF THREE-DIMENSIONAL DENDRITIC STRUCTURES IN NICKEL-BASE SINGLE CRYSTALS FOR INVESTIGATION OF DEFECT FORMATION
复制标题
用于缺陷形成研究的镍基单晶三维树枝状结构表征
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
T. Pollock
中科院分区：
文献类型：
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作者：
J. Madison;J. Spowart;D. Rowenhorst;J. Fiedler;T. Pollock
在凝固过程中，固液界面处溶质引起的对流不稳定性会导致高温合金单晶中形成斑点和取向错误的晶粒等缺陷。这些缺陷对单晶镍基高温合金的性能尤其不利。不幸的是，对树枝状结构尺度上的流体流动的详细理解尚未完全理解，特别是在非轴向排热的条件下。本研究的目的是开发一种量化固液界面处的枝晶结构和形态的技术，以便为计算流体流动模型提供直接输入。使用 RoboMET.3D 串行切片系统，获得了在凝固过程中突然倾析的 Rene N4 凝固前沿树枝状结构的三维数据集。分析了枝晶尖端附近固体和液体的分布和排列，并讨论了对缺陷形成的影响。
During solidification, solute-induced convective instabilities at the solid - liquid interface can result in the formation of defects such as freckles and misoriented grains in superalloy single crystals. These defects can be particularly detrimental to the properties of single crystal nickel-base superalloys. Unfortunately, detailed understanding of fluid flow at the scale of the dendritic structure has yet to be fully understood, particularly under conditions in which heat extraction is non-axial. The objective of this research is to develop a technique for quantifying the dendritic structure and morphology at the solid ‐ liquid interface for the purpose of providing direct input into computational fluid flow modeling. Using the RoboMET.3D serial sectioning system, threedimensional datasets of dendritic structure at the solidification front have been obtained for Rene N4 abruptly decanted during solidification. Distribution and arrangement of solid and liquid in the vicinity of dendrite tips is analyzed and the implications for defect formation are discussed.