Effect of Zr on solidification and microstructure of a Ni-based superalloy with high Al and Ti contents  

作　　者：Guang-di Zhao Xi-min Zang Fang Liu Wei-wei Zhang Shuo Gao Xue Li Jing Guo 

机构地区：[1]School of Materials and Metallurgy,University of Science and Technology Liaoning,Anshan 114051,Liaoning,China [2]Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China

出　　处：《China Foundry》2022年第1期17-26,共10页中国铸造（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Grant No.51904146)。

摘　　要：The total content of Al and Ti in advanced Ni-based wrought superalloys is up to 7.5wt.%,which makes it easier to form harmful nonequilibrium eutectic(γ+γ′)andηphase.It has been reported that the addition of certain amount of Zr can modify precipitation of the nonequilibrium phases obviously,but the mechanism is still controversial.The effect of Zr ranging from<0.0006wt.%to 0.150wt.%on solidification behavior,segregation and microstructure of a Ni-based superalloy with high Al and Ti contents was investigated,eliminating the interferences of C and B.Results show that increase in Zr content significantly promotes the formation of eutectic(γ+γ′),ηand Zr-rich phase in the interdendritic region.Besides the Zr-rich phase,Zr dissolves slightly in the eutecticγ′and obviously in theηphase.An interesting phenomenon is discovered that the Zr addition significantly increases the area fraction of liquid pools and enlarges the forming range ofγdendrites,which suggests that Zr markedly retards the solidification.Zr affects the eutectic(γ+γ′)andηformation mainly due to the retard of solidification and dissolution of Zr in them.The retard of solidification obviously increases the residual liquid fraction and undercooling.Zr can serve as a forming element for the eutectic(γ+γ′)andηphase,and the obvious dissolution of Zr inηphase significantly decreases the critical concentration of Ti for its precipitation.

关 键 词：ZIRCONIUM Ni-based superalloy solidification behavior SEGREGATION 

分 类 号：TG132.33[一般工业技术—材料科学与工程]