摘要
The microstructure and precipitation characteristics of 22Cr-14W-2Mo superalloys added with various La contents have been studied by SEM, TEM and EDX.It is found that the carbides are refined by adding La.M23C6 carbides inside the grain in a diameter of 50 nm have a cube-cube orientation relationship with the matrix, and these precipitates on {111} planes align along 110 orientation.Since the large dissolved La atom will be a barrier to atom diffusion, it leads to an inhibiting effect on the carbides growing.M6C carbides are influenced by La-S phases.La-S phases formed in the center of M6C seem to be the heterogeneous nucleus of M6C to increase the nucleation ratio.It is also noticed that finer M6C carbides precipitated on the {111} planes of the matrix are around large M6C.The finer M6C carbides are caused by the special absorption effect of La-S phases.
The microstructure and precipitation characteristics of 22Cr-14W-2Mo superalloys added with various La contents have been studied by SEM, TEM and EDX.It is found that the carbides are refined by adding La.M23C6 carbides inside the grain in a diameter of 50 nm have a cube-cube orientation relationship with the matrix, and these precipitates on {111} planes align along 110 orientation.Since the large dissolved La atom will be a barrier to atom diffusion, it leads to an inhibiting effect on the carbides growing.M6C carbides are influenced by La-S phases.La-S phases formed in the center of M6C seem to be the heterogeneous nucleus of M6C to increase the nucleation ratio.It is also noticed that finer M6C carbides precipitated on the {111} planes of the matrix are around large M6C.The finer M6C carbides are caused by the special absorption effect of La-S phases.
基金
supported by the Program for Changjiang Scholars and Innovative Research Teams in Chinese Universities (No. IRT0713)
the National Natural Science Foundation of China (No. 50841025)
