Abstract Refinement of dendritic microstructure in CMSX-4 Ni-based single crystal casting blade, manufactured using standard adjusted (ARB) or novel inner radiation baffles (IRBs) in the industrial-scale Bridgman solidification process, was investigated in the paper. Temperature gradient in the blade was mainly controlled by baffle geometry and by changing local solidification rate along casting height. Results showed that the use of relatively simple modification of mold, by introducing IRBs, resulted in increase of temperature gradient and noticeable refinement of dendritic microstructure. Temperature gradient in airfoil of blade increased by 30 and 95%, while primary dendrite arm spacing (PDAS) was favorably reduced by 7.8 and 21% for ARB and IRBs, respectively, compared with standard ring radiation baffle. The use of IRBs and ARB resulted in increase of tendency to form sliver defect in airfoil and low angle grain boundary in blade platforms. However, length of freckle chains decreased at root edge of blades when IRBs were used. New design and a proposal of the implementation of IRBs technique for the production of large IGT blades using Bridgman method were also discussed in this article.

中文翻译：

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在工业规模的布里奇曼凝固过程中通过改进热辐射屏蔽来细化单晶镍基高温合金的组织

摘要 本文研究了在工业规模的布里奇曼凝固过程中使用标准调整 (ARB) 或新型内辐射挡板 (IRB) 制造的 CMSX-4 镍基单晶铸造叶片中枝晶组织的细化。叶片中的温度梯度主要由挡板几何形状和沿铸件高度改变局部凝固速率来控制。结果表明，使用相对简单的模具修改，通过引入 IRB，导致温度梯度的增加和枝晶显微组织的显着细化。与标准环形辐射挡板相比，ARB 和 IRB 的叶片翼型温度梯度增加了 30% 和 95%，而一次枝晶臂间距 (PDAS) 分别有利地减小了 7.8% 和 21%。IRB 和 ARB 的使用导致在翼型和叶片平台中形成小角度晶界的长条缺陷的趋势增加。然而，当使用 IRB 时，叶片根部边缘的雀斑链长度减少。本文还讨论了使用布里奇曼方法生产大型 IGT 叶片的 IRB 技术的新设计和实施建议。