定向凝固镍基高温合金DZ125平界面生长的微观组织演化
收稿日期: 2010-04-21
修回日期: 2010-06-16
网络出版日期: 2010-09-11
基金资助
国家自然科学基金项目50827102, 国家重点基础研究发展计划项目2010CB631202和凝固技术国家重点实验室自主课题28-TP-2009资助
MICROSTRUCTURAL EVOLUTION OF DIRECTIONALLY SOLIDIFIED Ni-BASED SUPERALLOY DZ125 UNDER PLANAR GROWTH
Received date: 2010-04-21
Revised date: 2010-06-16
Online published: 2010-09-11
Supported by
Supported by National Natural Science Foundation of China (No.50827102), National Basic Research Program of China (No.2010CB631202) and the Research Fund of State Key Laboratory of Solidification Processing (NWPU) (No.28-TP-2009)
采用液态金属冷却(LMC)定向凝固技术, 对镍基高温合金DZ125在凝固速率为1.5 μm/s的条件下其平界面生长的微观组织演化规律进行了研究. 结果表明: 凝固组织演化经历3个不同的阶段, 当凝固分数fs<0.26时, 为单相γ组织, 基体中零星分布着细小的颗粒状的未熔HfC; 当0.26<fs<0.86时, 为γ/MC共生组织, MC为纤维状或者板片状; 当fs>0.86时, 为 γ/γ´共晶组织和分布于其中的粗大块状$M$C. EPMA结果表明: Al, Ti, Ta和Mo含量随fs的增大而增大; 而W, Cr和Co含量随fs的增大而减小. 分析指出, 凝固组织转变是由于溶质再分配产生的宏观溶质分布不均匀造成的.
闵志先 , 刘林 , 沈军 , 冯周荣 , 王灵水 , 傅恒志 . 定向凝固镍基高温合金DZ125平界面生长的微观组织演化[J]. 金属学报, 2010 , 46(9) : 1075 -1080 . DOI: 10.3724/SP.J.1037.2010.00185
By using liquid metal cooling method, the Ni-based superalloy DZ125 was directionally solidified under planar interface growth condition of drawing rate of 1.5 μm/s. The microstructures at different solidified fractions were examined by OM and SEM. The results showed that the solid/liquid interface is planar and the microstructure evolution undergoes three stages: the γ phase was formed as solidified fraction (fs) was not more than 0.26, and the fine HfC phase sparsely distributed in γ matrix; the coupled γ/MC growth appeared as fs ranged from 0.26 to 0.86, and the morphology of MC was fibrous or plate-like shapes; the γ/γ´ eutectic was obtained as fs was more than and equaled 0.86 0.86, in which the octahedral MC was precipitated simultaneously. EPMA was used to determine the solute distribution along the longitudinal direction of the sample. The contents of Al, Ti, Ta and Mo increased with fs increasing, while the contents of W, Cr and Co decreased. The analysis showed that the microstructure transformation is attributed to macro-scale non-uniform solute distribution which resulted from solute redistribution during directional solidification.
[1] Fu H Z. J Aeronaut Mater, 1998; 18(4): 52
(傅恒志. 航空材料学报, 1998; 18(4): 52)
[2] McLean M. Directionally Solidified Materials for High Temperature Service. UK: The Metals Society, 1983: 11
[3] Liu L, Huang T W, Zhang J, Fu H Z. Mater Lett, 2007; 61: 227
[4] Versnyder F I, Shank M E. Mater Sci Eng, 1970; A6: 213
[5] Tien J K, Gamble R P. Mater Sci Eng, 1971; A8: 152
[6] Bae J S, Lee J H, Kim S S, Jo C Y. Scr Mater, 2001; 45: 50
[7] Sellamuthu R, Giamei A F. Metall Mater Trans, 1986; 16A: 419
[8] Seo S M, Lee J H, Yoo Y S, Jo C Y, Miyahara H, Ogi K. In: Reed R C, Green K A, Caron P, Gabb T P, Fahrmann M G, Huron E S, Woodard S A. eds, Superalloys 2008, Warrendale, PA: TMS, 2008: 2773
[9] Stefanescu D M. Science and Engineering of Casting Solidification. New York: Kluwer Academic/Plenum Publishers, 2002: 33
[10] Trivedi R, Minyahara H, Mazumder P, Simsek E, Tewari S N. J Cryst Growth, 2001; 222: 365
[11] Tiller W A. Trans TMS–AIME, 1959; 215: 555
[12] Liu L, Sommer F, Fu H Z. Scr Metall Mater, 1994; 30: 584
[13] ZhangWG. PhD Thesis, Northwestern Polytechnical University, Xi’an, 2009
(张卫国. 西北工业大学博士论文, 西安, 2009)
[14] Li R J. Ceramic–Metal Composites. Beijing: Metallurgical Industry Press, 2004: 39
(李荣久. 陶瓷-金属复合材料, 北京: 冶金工业出版社, 2004: 39)
[15] Bhambri A K, Kattamis T Z, Morral J E. Metall Mater Trans, 1986; 6B: 523
[16] Chen J, Lee J H, Jo C Y, Choe S J, Lee Y T. Mater Sci Eng, 1998; A247: 113
/
| 〈 |
|
〉 |
