A dislocation density based material model to simulate the anisotropic creep behavior of single-phase and two-phase single crystals
The primary and secondary creep behavior of single crystals is observed by a material model using evolution equations for dislocation densities on individual slip systems. An interaction matrix defines the mutual influence of dislocation densities on different glide systems. Face-centered cubic (fcc), body-centered cubic (bcc) and hexagonal closed packed (hcp) lattice structures have been investigated. The material model is implemented in a finite element method to analyze the orientation dependent creep behavior of two-phase single crystals. Three finite element models are introduced to simulate creep of a gamma' strengthened nickel base superalloy in < 100 >, < 110 > and < 111 > directions. This approach allows to examine the influence of crystal slip and cuboidal microstructure on the deformation process.