一种镍基单晶叶片叶身-缘板转接区杂晶的形成机理  

Formation Mechanism of Stray Grain in the Transition Zone Between Airfoil and Platform of Nickel-Based Single Crystal Blade

作　　者：谭伟 薛鑫 于涛[2] 李维[1,3] 燕平 曾强[1,3] Tan Wei;Xue Xin;Yu Tao;Li Wei;Yan Ping;Zeng Qiang(High Temperature Materials Institute,Central Iron&Steel Research Institute,Beijing 100081,China;Institute of Functional Materials,Central Iron&Steel Research Institute,Beijing 100081,China;Beijing CISRI-GAONA Material&Technology Co.,Ltd,Beijing 100081,China)

机构地区：[1]钢铁研究总院高温材料研究所,北京100081 [2]钢铁研究总院功能材料研究所,北京100081 [3]北京钢研高纳科技股份有限公司,北京100081

出　　处：《稀有金属材料与工程》2022年第4期1348-1355,共8页Rare Metal Materials and Engineering

基　　金：国家重点研发计划(2017YFB0701503);国家自然科学基金(52073169)。

摘　　要：某种铸态镍基单晶叶片腐蚀后,观察到叶身-缘板转接区存在一种形状规则的条带状杂晶缺陷,且具有方向性,其长度方向平行(或垂直)于叶身和缘板的枝晶生长方向。采用光镜法(OM)、电子探针(EPMA)和电子背散射衍射技术(EBSD),分别研究了缺陷的组织、成分、取向,采用ProCAST模拟研究了缘板区域的温度场和过冷度分布。研究结果表明,叶身-缘板转接区杂晶缺陷由多个柱状晶粒构成;柱状晶粒的组织和成分与缘板基体一致,与基体的取向差形成小角度和大角度晶界;叶身-缘板转接区的过冷度比缘板边缘小,为缘板上的最后凝固区域。在此基础上,提出叶身-缘板转接区杂晶缺陷的形成机理,为消除该缺陷提供了理论基础。A stray grain with the regular shape was found in the transition zone between the airfoil and the platform of some single crystal blades after corrosion.The stray grain was band like and its length direction was parallel or perpendicular to the growth direction of dendrite in the airfoil and platform.The metallographic method(OM),electron probe microanalysis(EPMA),and electron backscatter diffraction(EBSD)were used to analyze the microstructure,composition and crystallographic relationship of the stray grain and its surrounding area,respectively.ProCAST was used to simulate the distribution of temperature field and undercooling of platform during solidification.The results show that the defect includes many columnar grains,whose composition is not significantly different from the airfoil or platform.However,the misorientation forms low angle grain boundaries or high angle grain boundaries between columnar grains and surrounding matrix.The undercooling of the transition zone between airfoil and platform is lower than that of the platform edge,and the transition zone is the final solidification area.Based on these results,the formation mechanism of defect in the transition zone between the airfoil and platform is proposed,which provides a theoretical basis for eliminating the defects.

关 键 词：镍基单晶高温合金 定向凝固 铸造缺陷 缘板杂晶 

分 类 号：TG146.15[一般工业技术—材料科学与工程]