| Title |
A Study on the γ' Size and Creep Properties of Mar - M247LC Superalloy |
| Authors |
강수현(Soo Hyeon Kang); 최병학(Byung Hak Choe); 허보영(Bo Young Hur); 김학민(Hak Min Kim) |
| Abstract |
Creep properties of Ni-base Mar-M247LC superalloy were investigated in the temperature range 760-980℃ as a function of the γ′ particle size. The particle size is shown to have a spectacular effect both on the creep behavior and stress rupture life in relation to the micro mechanism of plastic deformation. At the creep condition of 760℃-650MPa, the large γ′ size of 1.0㎛ results in optimum creep strength and rupture life of 150hrs. At higher temperatures, 870℃ and 980℃, the γ′ sizes which can improve on creep strength and life decrease to 0.5㎛ at 870-380MPa and 0.3㎛ at 980㎛-180MPa. The dislocation behavior of plastic deformation is related to the γ′ size and rupture life. In the large precipitates, the deformation occurred by homogeneous multiple slip in matrix leads rapidly to the formation of dense dislocation networks at the γ/γ′ interfaces and decreases the creep rate. Reducing the γ′ size promotes the heterogeneous deformation by shearing γ′ and leads to short rupture life. |