摘要
为研究Co对K4169合金凝固过程的影响,利用手工电弧炉熔炼制备了Co质量分数为0.5%～0.8%的合金,采用扫描电镜(SEM)、能谱仪(EDS)和电子探针(EPMA)对合金的凝固组织及元素偏析进行了研究.SEM观察结果表明,Co能强烈促进Laves相的形成,缩小合金枝晶间偏析区;随着Co质量分数从0.5%增加到0.8%,Laves相由小块状变为筛网状且数量明显增多.经SEM+EDS能谱和EPMA面扫描分析表明,Co能降低Nb在基体中的质量浓度,同时也能降低Fe和Cr在Laves相中的质量浓度而提高Nb、Mo、Ti在Laves相中的质量浓度,因而促进Laves相的析出.分析认为,过多增加Co质量分数对改善合金凝固组织的作用不大.
In order to investigate the effect of cobalt on the solidification process of K4169 superalloy,a manual electric arc furnace was used for preparing the superalloy with different cobalt content from 0.5% to 0.8%. The solidification microstructure and segregation were observed by SEM,EDS and EPMA. The results of SEM observation show that cobalt significantly promotes the formation of Laves phase and reduces the interdendritic segregation area. With increasing the Co content from 0.5% to 0.8%,the morphology of Laves phase changes from small block shape to mesh structure,and the amount of Laves phase increases considerably. The EDS and EPMA analyses show that cobalt can lower the solubility of Nb in the matrix. At the same time,cobalt can decrease the solubility of Fe and Cr in Laves phase,while increase the solubility of Nb,Mo and Ti in Laves phase. Therefore,it can be thought that cobalt promotes the precipitation of Laves phase. The analysis shows that the excessive increase of the Co content has little effect in improving the solidification microstructure of the K4169 alloy.
出处
《沈阳工业大学学报》
EI
CAS
2010年第4期385-389,共5页
Journal of Shenyang University of Technology
基金
甘肃省自然科学基金资助项目(3ZS042-B25-028)
关键词
高温合金
钴
凝固组织
元素偏析
K4169合金
LAVES相
铌
凝固过程
superalloy
cobalt
solidification microstructure
segregation
K4169 alloy
Laves phase
niobium
solidification process
