Formation and stability of nano-scaled M23C6 carbide in a directionally solidified Ni-base superalloy

The precipitation of nano-scaled M23C6 carbide at intragranular regions (especially in dendritic core regions) has been systematically investigated in a directionally solidified Ni-base superalloy. The crystallographic orientation relationship between the M23C6 phase and the γ matrix phase was found to be (100)M23C6//(100)γ, [100]M23C6//[100]γ. Additionally, M23C6 carbide was very stable during creep and long-term thermal exposure, which makes the fine M23C6 carbide an effective strengthening phase in γ matrix.