Mar-M247 니켈기 초내열합금의 Υ＇상 석출과 성장에 관한 연구

The precipitation and growth behaviors of γ′ phase in Mar-M247 type Ni-base Superalloy have been investigated mainly by micro-Vickers hardness test, scanning electron microscopy, transmission electron microscopy and electrical resistivity measurements. The γ′ precipitates were observed to be spherical at the early stage of aging time at all aging temperature and to be cuboidal at the later stage at 920, 970℃. The hardness of specimens aged in various conditions closely related to the size of γ′ precipitates. The growth kinetics of γ′ precipitates followed the prediction of Lifshitz-Slyozov-Wagner(L-S-W) theory of diffusion controlled growth at all aging temperatures(820, 870, 920, 970℃). The activation energy for the growth of γ′ precipitates was estimated 233kJ/㏖ which was nearly similar to those of diffusion for solute atoms(Co,Cr,Ti) in Ni₃Al and Ni-base Superalloys.