摘要
研究了横向磁场对镍基高温合金DZ417G定向凝固显微组织的影响。在较低生长速率条件下,磁场显著影响合金的枝晶生长和宏观偏析。施加磁场后一次枝晶间距减小并在沿磁场方向试样的左侧出现了"斑状"偏析。随着生长速率的增加,磁场的影响减弱。从磁场在合金熔体中诱发热电磁对流,并影响枝晶生长的角度对实验结果进行了分析。
Some problems still exist in the directionally solidified superalloy,such as coarse dendritic structure,thick second phase and composition segregation.Many efforts have been made to enhance the overall performance of superalloy by improving the components and processes.However, the higher alloying degree not only increases the solidification segregation,but also increases the tendency of precipitatingσ-phases,Laves-phases,μ-phases and other harmful phases.Therefore,it is crucial to improve the processes in order to enhance the performance of superalloy.It was known that the magnetic field effect is very obvious during the melt solidification process,which has been realized in the directional solidification of silicon,while the research on the magnetic field effect during the superalloy solidification process is few.So it is necessary to research the effect of magnetic field on directionally solidified superalloy.In this paper,the influence of horizontal magnetic field(≤0.8 T) on the microstructures of the superalloy DZ417G during directional solidification was investigated.It was found that the magnetic field can induce the appearance of freckle-like macrosegregation and the decrease of the primary dendrite arm spacing at a low growing speed,however,with the increase of the growth speed,the effects become weak.Based on the thermoelectric magnetic convection(TEMC) induced by the magnetic field during solidification and the effect of the convection on the microstructure, the above experimental results were discussed and analyzed.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第1期71-76,共6页
Acta Metallurgica Sinica
基金
长江学者创新团队发展计划项目IRT0739
上海市科学技术委员会项目071005130和08dj1400404
上海市教育委员会项目
国家自然科学基金项目50801045和50701031资助~~
关键词
镍基高温合金
横向磁场
定向凝固
热电磁对流
Ni-based superalloy
horizontal magnetic field
directional solidification
thermoelectric magnetic convection