Ni-Cr-Co基高溫合金中微量元素鎂的偏析規律

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

摘要: 應用俄歇能譜儀(AES)研究了Ni-Cr-Co基高溫合金中微量Mg的偏析規律。結果表明,偏析于晶界的Mg具有平衡偏析的特性;同時Mg的這種偏析在900℃附近速度最快。分析認為,這是由于偏析熱力學和動力學共同控制的結果,也與該合金中碳化物M₆C在晶界上析出有內在聯系。研究中還發現,Mg在晶界上分布是不均勻的,且這種不均勻性隨時效時間的延長而增加。
研究中還應用透射電鏡能譜(TEM)分析了Mg的分布,得到與AES類似的結果,進一步驗證Mg在奧氏體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.