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薄板试样定向凝固枝晶竞争生长
引用本文:杨泽南,张 朕,郭春文,潘 昊,王 祯,张 强,黄朝晖,王志军.薄板试样定向凝固枝晶竞争生长[J].稀有金属材料与工程,2021,50(4):1247-1253.
作者姓名:杨泽南  张 朕  郭春文  潘 昊  王 祯  张 强  黄朝晖  王志军
作者单位:中国航发北京航空材料研究院 先进高温结构材料重点实验室,东北大学 轧制技术及连轧自动化国家重点实验室,郑州大学 材料科学与工程学院,西北工业大学凝固技术国家重点实验室,中国航发北京航空材料研究院 先进高温结构材料重点实验室,中国航发北京航空材料研究院 先进高温结构材料重点实验室,中国航发北京航空材料研究院 先进高温结构材料重点实验室,中国航发北京航空材料研究院 先进高温结构材料重点实验室;东北大学 轧制技术及连轧自动化国家重点实验室;郑州大学 材料科学与工程学院;西北工业大学凝固技术国家重点实验室
基金项目:本课题受中国航发产学研合作项目HFZL2018CXY022及航材院益材KJ53200134资助
摘    要:深入理解高温合金定向凝固杂晶演化具有重要的科学和工程意义,其中枝晶竞争生长是揭示晶界演化与淘汰的关键环节。定向凝固双晶竞争生长的实验研究证实了传统尖端过冷度理论的局限性,定量相场模拟的研究获得了大量统计规律,促进了人们对定向凝固双晶竞争生长的理解。本研究在薄板状试样的定向凝固过程中,同时获得了大量的不同取向竞争生长的枝晶,通过拼接金相显微组织同时获得多个晶界的取向演化规律。结果表明,枝晶列竞争生长主要通过晶界两侧不同取向一次枝晶臂及二次枝晶臂的交互作用实现。在汇聚生长过程中,择优枝晶一次臂阻挡非择优枝晶,并且择优枝晶自身无法形成三次臂,导致晶界方向沿择优枝晶生长方向。发散生长过程中,处于温度梯度方向一侧时,两列枝晶的竞争生长方式以非择优枝晶新生三次臂为主,晶界以沿择优枝晶方向生长为主;当两列枝晶处于温度梯度不同侧时,两列枝晶均有三次臂新生的概率,其晶界在两列枝晶取向之间。实验统计结果给出了晶界随两列竞争生长枝晶的取向的变化规律,与定量相场模拟结果吻合。商业软件ProCAST的CAFE计算晶粒定向竞争生长晶界演化统计结果与实验结果存在较大偏差,其主要原因是CAFE仅给出晶粒尺度的轮廓信息,未考虑溶质扩散及二次臂的竞争。本研究获得的薄板状试样枝晶竞争生长的统计规律,对认识高温合金定向凝固过程中晶界取向的演化具有重要的意义,对柱状晶叶片的制备具有指导意义。

关 键 词:定向凝固  竞争生长  晶界取向
收稿时间:2020/10/21 0:00:00
修稿时间:2020/11/16 0:00:00

The competitive growth of dendrite arrays in the directional growth of a thin sample
Yang Zenan,Zhang Zhen,Guo Chunwen,Pan Hao,Wang Zhen,Zhang Qiang,Huang Chaohui and Wang Zhijun.The competitive growth of dendrite arrays in the directional growth of a thin sample[J].Rare Metal Materials and Engineering,2021,50(4):1247-1253.
Authors:Yang Zenan  Zhang Zhen  Guo Chunwen  Pan Hao  Wang Zhen  Zhang Qiang  Huang Chaohui and Wang Zhijun
Affiliation:Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang,School of Materials Science and Engineering,Zhengzhou University,,Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,
Abstract:The high performance blade has been the widely applied to increase the efficiency of the aircraft engine, and its fabrication has been well developed. However, the appearance of misoriented grains always decrease of production yield. Competitive growth of dendrite arrays with different orientation in directional solidification is an important phenomenon for the fabrication of single crystal blade. The question has caught attention for many years. The tip undercooling has been the only criterion for the elimination of unrefereed dendritic grains for a long time and is implanted in commercial software ProCAST to simulate the grain growth. However, the experimental bicrystal growth in directional solidification identified the drawback of the tip undercooling criterion. Quantitative phase field simulations showed more details of the bicrystal competitive growth. The grain boundary evolution has been one of the key indicators for competitive growth. The previous tip undercooling criterion could not predict the grain boundary evolution. The huge phase field simulations reveal the statistic evolution rule of the grain boundary direction. In this paper, we proposed a sheet sample with multiple bycrystals configurations. The microstructures were observed in a stitching picture. The competitive growth and the grain boundary selection of dozens of biocrystals have been summarized within several samples. The statistical results agree with the phase field simulation. However, the CAFE simulation results from the ProCAST can not predict the grain boundary evolution. The method proposed here can be applied to investigate the competitive growth with a high throughput way. The results are helpful to understand the unoriented grains in fabrication of single crystal blade.
Keywords:directional  solidification  competitive  growth  grain  boundary direction
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