Carbide behavior during high temperature creep in DZ40M Co-based superalloy

摘要

The carbide behavior of a directionally solidified Co-based superalloy DZ40M has been investigated after creep at 700 deg. C and 900 deg. C. During the high temperature creep, a great amount of secondary carbide, M_23C_6 precipitated in alloy matrix. At 700 deg. C, the M_23C_6 precipitation occurred in slip bands, indicating that it was stress-induced, while at 900 deg. C, M_23C_6 formed surrounding the primary carbides, which is a characteristics of thermaly aged alloy.