高合金化GH742合金存在严重的枝晶偏析,Nb、Ti大量偏聚于枝晶间,导致MC碳化物、(γ+ γ′)共晶、Laves相、δ相等析出;高Mo含量及其枝晶间偏析是析出σ相的重要原因;La、Ce在枝晶间的富集促使含氧硫稀土相和Ni5Ce相的析出.与一般合金凝固特点不同,高含量Al、Ti、Nb导致GH742合金凝固过程中先后发生(γ+ γ′)和(γ+Laves)两种类型的共晶反应.结合差热分析技术和凝固组织特点确定了合金的凝固温度区间为1346-1190 ℃,凝固顺序为γ、MC、(γ+ γ′)、Laves、Ni_5Ce.
High alloying GH742 alloys exhibit severe dendritic segregation with Nb and Ti intensively segregated to the interdendritic regions, leading to the precipitation of MC carbide, (γ+γ′) eutectic, Laves phase and δ phase. High content of Mo as well as its dendritic segregation is the significant reason for the precipitation of σ phase. Two phases containing rare earth elements, Ni5Ce phase and RE-O-S phase, are precipitated in the interdendritic regions due to the enrichment of La and Ce. Different from other superalloys, both eutectic reactions of (γ+γ′) and (γ+Laves) take place in sequence during the solidification process of GH742 alloys owing to the high contents of Al, Ti and Nb. The solidification temperature range of GH742 alloys is between 1346 and 1190 oC, and the solidification sequence is γ, MC, (γ+γ′), Laves and Ni_5Ce, which is determined by differential thermal analysis and solidification microstructure characterization.
参考文献
| [1] | Zheng L;Gu C Q;Zheng Y R .[J].Scripta Materialia,2004,50:435. |
| [2] | Zhu Y X;Zhang S N;Zhang T X et al.Superalloys 1992[R].New York:The Minerals,Metals & Materials Society,1992. |
| [3] | Sun W R;Guo S R;Lu D Z et al.[J].Materials Letters,1997,31:195. |
| [4] | Wang A C;Li Y Y;Fan C G et al.[J].Scripta Metallurgica et Materialia,1994,31:1695. |
| [5] | 黄福祥.涡轮盘用变形高温合金在俄国的发展[J].航空材料学报,1993(03):49. |
| [6] | 谢永军,梁学锋,缪宏博,李伟.GH742合金钢锭的组织及偏析的消除[J].钢铁研究学报,2003(z1):17-20. |
| [7] | 田玉亮,王玲,董建新,张麦仓.GH742铸锭偏析及均匀化过程中元素分布规律[J].稀有金属材料与工程,2006(08):1315-1318. |
| [8] | Sponseller D L .Superalloys 1996[R].New York:The Minerals,Metals & Materials Society,1996. |
| [9] | Dupont J N;Robino C V;Michael J R et al.[J].Metallurgical and Materials Transactions A:Physical Metallurgy and Materials Science,1998,29:2785. |
| [10] | 孙晓峰,殷凤仕,李金国,侯贵臣,郑启,管恒荣,胡壮麒.一种铸造镍基高温合金的凝固行为[J].金属学报,2003(01):27-29. |
| [11] | Murata Y;Morinaga M;Yukawa N et al.Superalloy 718 625 706 and Various Derivatives[R].Warrendale,PA:TMS,1994. |
| [12] | 郭可信 .[J].金属学报,1978,14:73. |
| [13] | Ma P L;Zhu J .[J].METALL,1986,19:115. |
| [14] | 孙文儒 .[D].Shenyang:Institute of Metal Research,Chinese Academy of Sciences,1996. |
| [15] | Li D;Cosandey F;Maurer G E et al.[J].Metallurgical Transactions B,1982,13:603. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%