|
|
|
| the decomposition of metastable high temperature γ' precipitates in U720LI alloy |
| SONG Xiping; LI Hongyu; GAI Jingfeng; CHEN Guoliang |
| State Key Laboratory for Advanced Metals and Materials;University of Science and Technology Beijing |
|
Cite this article:
SONG Xiping; LI Hongyu; GAI Jingfeng; CHEN Guoliang. the decomposition of metastable high temperature γ' precipitates in U720LI alloy. Acta Metall Sin, 2005, 41(11): 1233-1236 .
|
|
|
Abstract The decomposition of spherical γ' phase precipitated at high temperature during continuous cooling of U720LI Ni-based alloy has been studied. Fast cooling from supersaturated γ solid solution of the alloy could not inhibit fine γ'precipitates, and the size of the γ' precipitates is about 40-60 nm.When slow cooling to 650℃ and then fast cooling to the room temperature, two kinds of γ' precipitates were found. One was precipitated at high temperature with the size about 200 nm and another was precipitated at low temperature with the size of 50-65 nm in average. Moreover, the big γ' precipitates which precipitated at high temperature were found to be decomposed to form finer γ' precipitates. Because the high
temperature γ'\γ interface offers necessary
condition for non-classical nucleation theory,
any segregation area of γ' formation elements at the high temperature γ'/γ interface can act as pre-existed γ'nuclei and thus promote the precipitation of finer γ' from the saturated γ matrix. Through the short-distance diffusion of the γ' formation
elements from the high temperature γ' to pre-existed γ' nuclei, the pre-existed γ' nuclei can grow to be 10-20 nm in size. At the same time, the high temperature γ' precipitates became instable due to loss of γ' formation elements and began to be decomposed as a result. The subsequent ageing promotes the
decomposition of the big high temperature γ'.
|
|
Received: 30 June 2005
|
|
|
[1] Yeom S J, Yoon D Y, Henry M F. Metall Trans, 1993;24A:1975
[2] Qiu Y Y. J Alloys Compd, 1998; 270: 145
[3] Furrer D U, Fecht H J. Scr Mater, 1999; 40: 1215
[4] Doi M, Miyazaki T, Wakatsuki T. Mater Sci Eng, 1984;67:247
[5] Doi M, Miyazaki T. Mater Sci Eng, 1986; 78: 87
[6] Doi M. Mater Trans JIM, 1992; 33: 637
[7] Klepser C A. Scr Metall, 1995; 33: 589
[8] Kusabiraki K, Zhang X M, Ooka T. ISM Int, 1995; 35:1115
[9] Chen G L. Superalloys. Beijing: Metallurgical Industry Press, 1987 (陈国良．高温合金学．北京:冶金工业出版社,1987)
[10] Yu Y N. Principle of Metallurgy. Beijing: Metallurgical Industry Press, 1987 (余永宁,金属学原理．北京:冶金工业出版社, 2000)
[11] Chen G L, Yao K F, Kou H C, Hui X D. Prog Nat Sci, 2003; 13: 1022 (陈国良,姚可夫,寇宏超,惠希东．自然科学进展,2003;13: 1022)
[12] Blavette D, Bostel A, Sarrau J M. Metall Trans, 1985; 16A: 1703 |
| No Suggested Reading articles found! |
|
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
