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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M_6C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。
The segregation of trace Mg in Ni-Cr-Co-based superalloy was studied by Auger spectroscopy (AES). The results show that the segregation of Mg in the grain boundary has the characteristics of equilibrium segregation; meanwhile, the segregation of Mg is the fastest near 900 ℃. It is considered that this is the result of the common control of segregation thermodynamics and kinetics and is also intrinsically linked to the precipitation of carbides M_6C on the grain boundaries. The study also found that the distribution of Mg in the grain boundary is not uniform, and this non-uniformity increases with the aging time. In the study, the distribution of Mg was also analyzed by transmission electron microscopy (TEM), and the results similar to AES were obtained. The above characteristics of Mg segregation at austenite grain boundaries were further verified.