Influence of interface energies on solute partitioning mechanisms in doped aluminas

摘要

The experiments described in this paper have been designed to understand how particular dopants in alumina (Ca, Mg, Si, and Y)affect microstructural development through the energetics of their associated precipitates. Specifically, the role of the interphase bound-ary energy and precipitation activation energy are considered to be in competition with grain boundary complexion (disorder) transitionsfor partitioning excess solute. The results reveal a relationship between the relative precipitation activation energy and the temperature atwhich grain boundary complexion transitions occur. The large differences in activation energy primarily derive from the interphaseboundary energy. Precipitates that form lower interphase boundary energies tend to suppress complexion transitions, while systems thatcontain precipitates with high interphase boundary energies are more susceptible. Based on the findings, a new criterion for additiveselection to control complexion transitions and abnormal grain growth is proposed that is based on interfacial energies between the hostand precipitate.