Abstract
Polycrystalline Ni-base superalloys are used for turbine blades in power plants and jet engines. In order to ensure safety in these systems, clarifying the behavior and mechanism of creep damage formation is highly in need. Thus in this study, elastic-plastic-creep finite element analysis combined with vacancy diffusion analysis was conducted for polycrystalline Ni-base superalloy model in order to mechanically examine the creep damage formation behavior. FEM and vacancy diffusion were combined in this analysis in the interest of considering both macro and micro damages. As the result of the analysis, damage caused by plastic deformation and vacancy, which forms voids when coalesced, were found to accumulate at grain boundary, which eventually lead to intergranular cracking. Furthermore, by combining FEM and vacancy diffusion analyses, macro damage region was detected by FEM analysis, and micro damage region within the macro damage region was detected by vacancy diffusion analysis.
