两种型壳温度对DD9单晶涡轮叶片凝固组织的影响  

Effect of two mould temperatures on solidification microstructures of DD9 single crystal turbine blade

作　　者：薛燕鹏 王效光 赵金乾 史振学 刘世忠 李嘉荣 XUE Yanpeng;WANG Xiaoguang;ZHAO Jinqian;SHI Zhenxue;LIU Shizhong;LI Jiarong(Science and Technology on Advanced High Temperature Structural Materials Laboratory,AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]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,北京100095

出　　处：《材料工程》2022年第7期80-87,共8页Journal of Materials Engineering

基　　金：国家科技重大专项(2017-Ⅵ-0001-0070)。

摘　　要：为了研究1500℃和1540℃两种型壳温度对第三代单晶高温合金DD9叶片截面凝固组织的影响,采用光学显微镜、扫描电子显微镜对叶片典型截面凝固组织进行分析。结果表明:随着型壳温度的增加,DD9单晶涡轮叶片凝固组织的枝晶花样呈细小趋势,二次枝晶呈发达趋势。相同型壳温度下,叶片叶身部位的枝晶比榫头部位的枝晶更细小。随着型壳温度的增加,枝晶干和枝晶间的γ′析出相尺寸和分散度均减小,并且γ′析出相尺寸分布遵循正态分布规律。相较枝晶间区域,枝晶干区域的γ′析出相的平均尺寸减小了61%。相同型壳温度下,叶片叶身部位的γ′析出相尺寸比榫头部位的γ′析出相尺寸更细小。与截面积变小相比,提高型壳温度会使γ′析出相变小更显著。随着型壳温度的增加,γ-γ′共晶尺寸和含量减小,γ-γ′共晶组织呈葵花状和光板状两种形貌特征。In order to investigate the solidification microstructures in typical section dimensions of a third generation single crystal superalloy DD9 turbine blade with 1500℃and 1540℃mould temperatures during directional solidification process,Optical microscopy(OM)and scanning electron microscopy(SEM)were used to analyse the solidification structure of typical sections of the blade.The results show that with increasing mould temperatures,the dendrite patterns have a tendency of becoming more refined,and the secondary dendritic arms tend to be highly developed.With the same mould temperature,the dendrite patterns in the blade aerofoil section are more refined than those in the tenon section.Also with increasing mould temperatures,theγ′precipitates of the interdendritic regions and the dendritic cores tend to be refined,theγ′precipitation size dispersion decreases,and the size distributions of theγ′precipitates follow the normal distribution law.Compared with the interdendritic regions,almost 61%reduction of theγ′precipitation average sizes is measured in the dendritic core.With the same mould temperature,theγ′precipitation sizes in the aerofoil section are more refined than those in the tenon section.Compared with the decreasing sectional areas,the increasing mould temperatures bring down theγ′precipitation sizes obviously.The sizes and contents of theγ-γ′eutectics decrease with increasing mould temperatures.The morphologies ofγ-γ′eutectics show both sunflower-like shape and plate-like shape.

关 键 词：单晶高温合金 DD9 型壳温度 凝固组织 

分 类 号：TG132.3[一般工业技术—材料科学与工程]