A simple FE approach to study microstructural influences in power-law creep

Creep of metallic materials is a complex phenomenon, which is depending on temperature, time, the applied load and the specific properties of the material exposed to creep conditions. Especially the influence of the microstructure on creep phenomena is complex, thus a comprehensive finite element model is used to study the heterogeneous deformation on a microstructural level. The different microstructural components are incorporated by using distinct, individual sets of physical parameters for each constituent. The materials response is calculated in terms of creep strains and stresses using a simple approach to simulate power-law creep and the influence of grain boundaries, triple junctions and precipitates on creep strains and stresses is studied.The results indicate that the different microstructure configurations, such as the presence of triple points, second phase particles and the relative orientation of grain boundaries to the loading direction influence the stress distribution and therefore lead to a highly heterogeneous creep strain distribution.

Creep behaviour is strongly influenced by a materials’ microstructure. In this study, a simple approach is used to model power-law creep. The FE method is used to simulate the heterogeneous creep strains and stresses. The orientation of grain boundaries to the loading direction affects local stresses. Especially triple points are causing inhomogeneities in the creep straining material.