Effect of lanthanum on microstructure of a nickel-based single crystal superalloyOA
To enhance the high-temperature oxidation resistance and mechanical properties of a secondgeneration nickel-based superalloy,various concentrations of lanthanum(La)ranging from 5.0×10^(-5)wt.%to 3.4×10^(-4)wt.%are added to the alloy.The microstructure of the nickel-based single crystal superalloy with trace of La was examined by means of SEM,EDS and TEM.Results show the addition of La decreases the segregation of elements and increases the amount ofγ/γ′eutectics of the as-cast alloy,and in the interdendritic region,the growth of eutectics is accompanied by the growth of strip clusters composed of Ni_(5)La and Ni_(3)Ta.As the La content in the alloy increases,the proportion of Ni_(5)La in the cluster increases.After heat treatment,incipient melting occurs in the cluster regions,leading to an increase in microporosity compared to the original as-cast samples.Furthermore,the heat treatment alters the shape of the clusters from a strip morphology to an elliptical one,and it changes their composition from Ni_(5)La and Ni_(3)Ta to a combination of Ni_(5)La,Ni_(3)Ta,and MC carbides.
Hong Gao;Kai Guan;Ren-jie Cui;Jian-chao Qin;Zi-han Zhao;Zhao-hui Huang
Science and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,ChinaScience and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,ChinaScience and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,ChinaScience and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,ChinaScience and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,ChinaScience and Technology on Advanced High Temperature Structural Materials Laboratory,Beijing Institute of Aeronautical Materials,Beijing 100095,China
金属材料
single crystal superalloylanthanummicrostructureheat-treatmentprecipitate phase
《China Foundry》 2025 (1)
P.55-64,10
funded by the National Science and Technology Major Project of China(Grant No.J2019-Ⅵ-0023-0139)。
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