Effect of grain boundary carbides on the diffusion behavior of Te in Ni-16Mo-7Cr base superalloy

Abstract Fission product Te could result in intergranular embrittlement of Ni-16Mo-7Cr superalloy and threaten the safety of molten salt reactor. Although embrittlement of Te has been reported widely, there are few researches about the influence of precipitated grain boundary carbides (M12C) on the diffusion behavior of Te in the alloy with long term service. In this study, the effect of M12C on the diffusion behavior of Te in Ni-16Mo-7Cr alloy was studied. The results showed that Cr3Te4 and Ni3Te2 were formed along M12C at the grain boundary of alloy after long-term thermal exposure. However, the formation of M12C carbides and tellurides had little impact on the diffusion of Te in the alloy.