航空学报 > 1992, Vol. 13 Issue (1): 117-120

宽变冷速对定向凝固合金枝晶偏析的影响

李建国, 储双杰, 刘忠元, 傅恒志   

  1. 西北工业大学403教研室 西安 710072
  • 收稿日期:1990-08-11 修回日期:1990-11-20 出版日期:1992-01-25 发布日期:1992-01-25

EFFECT OF WIDE CHANGE OF COOLING RATE ON DENDRITIC SEGREGATION OF A DIRECTIONALLY SOLIDIFIED COBALT-BASE SUPERALLOY

Li Jian-guo, Chu Shuang-jie, Liu Zhong-yuan, Fu Heng-zhi   

  1. Faculty 403 of Northwestern Polytechnical University, Xi'an, 710072
  • Received:1990-08-11 Revised:1990-11-20 Online:1992-01-25 Published:1992-01-25

摘要:

利用多种定向凝固技术,研究了冷却速率在10~(-2)~10~2K/s范围内变化时对定向凝固钻基高温合金枝晶偏析的影响。结果表明:增大冷却速率可有效抑制枝晶偏析,对易偏析元素其效果更明显;冷却速率的增大细化了凝固组织的一次间距、加剧了溶质的非平衡分凝是抑制偏析的主要原因。

关键词: 定向凝固, 冷却速率, 高温合金, 枝间偏析

Abstract:

The temperature gradient and the growth rate are the two main parameters of a directional solidification process, which may be expressed synthetically as the cooling rate. In this paper, various directional solidification techniques have been used in the research of dendritic segregation of a cobalt-base superalloy during directional solidification with the cooling rate between 10-2-102K/s. Results show that the increase of cooling rate can restrain dendritic segregation effectively, especially for easily segregated alloy elements. Two mechanisms are favourable in the restraint of dendritic segregation: one is the microstructure refinement by increasing cooling rate, another is non-equilibrium partitioning of solutes at the solid/liquid interface which makes the partitioning coefficient tend to unity.

Key words: directional solidification, cooling rate, superalloy, dendritic segregation