The primary and secondary creep behaviour of single crystals was 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, body-centered cubic and hexagonal closed packed lattice structures were investigated. The material model was implemented in a finite element method to analyze the orientation dependent creep behaviour of two-phase single crystals. Three finite element models were introduced to simulate creep of a γ′ strengthened nickel base superalloy in <100>, <110> and <111> directions. This approach allowed to examine the influence of crystal slip and cuboidal microstructure on the deformation process.

A Dislocation Density Based Material Model to Simulate the Anisotropic Creep Behaviour of Single-Phase and Two-Phase Single Crystals. J.Preussner, Y.Rudnik, H.Brehm, R.Völkl, U.Glatzel: International Journal of Plasticity, 2009, 25[5], 973-94