%0 journal article
%@ 0966-9795
%A Wang, L., Oehring, M., Lorenz, U., Stark, A., Pyczak, F.

%D 2018
%J Intermetallics

%P 70-76 
%R doi:10.1016/j.intermet.2018.06.006
%T New insights into perovskite-Ti3AlC precipitate splitting in a Ti-45Al-5Nb-0.75C alloy by transmission electron microscopy
%U https://doi.org/10.1016/j.intermet.2018.06.006
 
%X The addition of carbon in TiAl alloys can improve the mechanical properties by precipitate hardening through the perovskite Ti3AlC carbide. Usually precipitates coarsen during continuous annealing. However, in the Ti-45Al-5Nb-0.75C alloy a splitting of the perovskite carbides was observed in later stages of annealing. By investigation with transmission electron microscopy the details of this splitting process are revealed after annealing at 900 °C. The results show that the re-orientation of the γ phase regions between sub-particles is associated with the splitting step from carbide needles into small sub-particles. γ domains with a different orientation with respect to the γ matrix nucleate and gradually replace the γ matrix phase in regions between the carbide sub-particles. The progress of the splitting process is locally different in different carbides and also in one individual carbide. By increasing the temperature from 800 to 900 °C the growth of the emerging carbide conglomerates and the splitting process of the carbides are greatly accelerated. It is found that both are diffusion-controlled processes.