重熔温度对Inconel718定向凝固过程中糊状区偏析和Rayleigh数的影响  

Effects of Remelting Temperature on the Segregation and Rayleigh Number in the Mushy Zone of Directionally Solidified Superalloy Inconel 718

作　　者：王玲[1] 许斌斌[1] 刘林[2] 董建新[3] 

机构地区：[1]南京信息工程大学,江苏南京210044 [2]西北工业大学凝固技术国家重点实验室,陕西西安710072 [3]北京科技大学,北京100083

出　　处：《稀有金属材料与工程》2017年第2期565-570,共6页Rare Metal Materials and Engineering

摘　　要：用扫描电镜(SEM)以及能谱分析方法(EDAX)研究了经不同重熔温度加热并以一定速率定向凝固的高温合金Incond718糊状区液相的显微组织和成分。给出了液相中Nb、Mo沿着糊状区的分布。同时计算了糊状区液相密度差和相对Rayleigh数(Rar)。当重熔温度从1600℃升高到1700℃,Mo偏析加重,糊状区变长,液相密度差在凝固初期变大,糊状区的极大值显著升高,这说明重熔温度提高后热溶质对流趋势增大,糊状区变得不稳定。Superalloy Inconel 718 was directionally solidified at various solidification rates after heating at different remelting temperatures.The microstructure and composition of the liquid along the mushy zone of the superalloy have been investigated by scanning electron microscope（SEM） and energy dispersion analysis spectrometry（EDAX）.The content of Nb and Mo in the interdendritic liquid along the mushy zone was given.The liquid-density difference and relative Rayleigh number in the interdendritic liquid were calculated.Results show that when the remelting temperature increases from 1600 ℃ to 1700 ℃,the segregation of Mo becomes more serious,the liquid-density difference becomes higher at the beginning of solidification and the maximum relative Rayleigh number（Rar） increases greatly,which indicates the tendency of thermal solute fluid flow becomes larger and mushy zone is more unstable.

关 键 词：高温合金 定向凝固 重熔温度 偏析 相对Rayleigh数 

分 类 号：TG132.3[一般工业技术—材料科学与工程] TG244.3[金属学及工艺—合金]