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。
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.
出处
《航空学报》
EI
CAS
CSCD
北大核心
1992年第1期A117-A120,共4页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金
航空科学基金
关键词
定向凝固
冷却速率
高温合金
directional solidification, cooling rate, superalloy, dendritic segregation
