Ni-Cr-Co基高温合金中微量元素镁的偏析规律

The Segregation Behaviours of Magnesium Addition in A Ni-Cr-Co Base Superalloy

摘要: 应用俄歇能谱仪(AES)研究了Ni-Cr-Co基高温合金中微量Mg的偏析规律。结果表明,偏析于晶界的Mg具有平衡偏析的特性;同时Mg的这种偏析在900℃附近速度最快。分析认为,这是由于偏析热力学和动力学共同控制的结果,也与该合金中碳化物M₆C在晶界上析出有内在联系。研究中还发现,Mg在晶界上分布是不均匀的,且这种不均匀性随时效时间的延长而增加。
研究中还应用透射电镜能谱(TEM)分析了Mg的分布,得到与AES类似的结果,进一步验证Mg在奥氏体晶界偏析的上述特性。

Abstract: The segregation behaviours of Mg addition in a Ni-Cr-Co base superalloy have been investigated. Both AES and EDS analysis on TEM thin film mold are used for measuring the segregation behaviours of Mg.
The results show that the equilibrium segregation of Mg in grain boundaries is taken place; the rate of the Mg segregation to grain boundaries is the fastest near 900℃. These have close interrelation with the segregation kinetics and thermodynamics and the carbides M₆C in grain boundaries. In addition, the distribution of Mg in grain boundaries is inhomogeneous, which the increase with increasing of ageing time.
Theuresults measured with AES and EDS analysis on TEM thin film mold are similar.