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. M_(23)C_6 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. M_6C carbides are influenced by La-S phases. La-S phases formed in the center of M_6C seem to be the heterogeneous nucleus of M_6C to increase the nucleation ratio. It is also noticed that finer M_6C carbides precipitated on the {111} planes of the matrix are around large M_6C. The finer M_6C carbides are caused by the special absorption effect of La-S phases.
参考文献
| [1] | Huang Q.Y;Li H.K.Superalloy[M].北京:冶金工业出版社,2002:246. |
| [2] | Chen Q.Z;Thomas C.W;Knowles D.M .Characterization of 20Cr32Ni1Nb alloys in as-cast and ex-service conditions by SEM,TEM,and EDX[J].Materials Science and Engineering A:Structural Materials Properties Microstructure and Processing,2004,374:398. |
| [3] | Safari J;Nategh S .On the heat treatment of Rene-80 nickel-base superalloy[J].Journal of Materials Processing Technology,2006,176:240. |
| [4] | Oh Y.K;Kim G.S;Indacochea J.E .Creep rupture behaviour due to molybdenum rich M_6C carbide in 1.0Cr-1.0Mo-0.25V bainitic steel weldment[J].Scripta Materialia,1999,44(01):7. |
| [5] | Liu L.R;Jin T;Zhao N.R;Sun X.F,Guan H.R,Hu Z.Q .Formation of carbides and their effects on stress rupture of a Ni-base single crystal superalloy[J].Materials Science and Engineering A:Structural Materials Properties Microstructure and Processing,2003,361:191. |
| [6] | Zhou P.J;Yu J.J;Sun X.F;Guana H.R,Hu Z.Q .Role of yttrium in the microstructure and mechanical properties of a boron-modified nickel-based superalloy[J].Scripta Materialia,2007,57(07):643. |
| [7] | Guo F.A;Xiang C.J;Yang C.X;Cao X.M,Mu S.G,Tang Y.Q .Study of rare earth elements on the physical and mechanical properties of a Cu-Fe-P-Cr alloy[J].Materials Science and Engineering B,2007,147:1. |
| [8] | Biju A;Vinod K;Aloysius R.P;Syamaprasad U .unproved superconducting properties by La addition in (Bi,Pb)-2212 bulk superconductor[J].Journal of Alloys and Compounds,2007,431:49. |
| [9] | Pelcová J;Smola B;Stulíková I .Influence of processing technology on phase transformations in a rare-earth-containing Mg-Zn-Zr alloy[J].Materials Science and Engineering A:Structural Materials Properties Microstructure and Processing,2007,462:334. |
| [10] | Wang R.M;Song Y.G;Han Y.F .Effect of rare earth on the microstructure and properties of a low expansion superalloy[J].Journal of Alloys and Compounds,2002,311(01):60. |
| [11] | Kim T.K;Baek J.H;Han C.H;Kim S.H,Lee C.B .Effects of the fabrication process parameters on the precipitates and mechanical properties of a 9Cr-2W-V-Nb steeL[J].Journal of Nuclear Materials,2009,389:359. |
| [12] | X.Z. Qin;J.T. Guo;C. Yuan;J.S. Hou;H.Q. Ye .Precipitation and thermal instability of M_(23)C_6 carbide in cast Ni-base superalloy K452[J].Materials Letters,2008(2):258-261. |
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