This paper presents a multiscale, crystal plasticity, model that may be used to study the deformation behaviour of second-generation nickel super-alloy, CMSX4. CMSX4 is one of the nickel super-alloys used in gas turbines for non-stationary components in aero-engines, such as turbine blades. Accurate knowledge of this material’s deformation behaviour is crucial to increase engine efficiency and life of the component but, even more so, to avoid catastrophic failure of critical components.

Primary creep deformation of CMSX4 is, for the most part, governed by the gliding of dislocations through the super-alloy’s g-g’ microstructure. Under these creep conditions it is the g’ precipitate that acts as pinning mechanism and hence results in dislocation retardation and material strengthening during deformation. It has been shown that primary creep of such alloys is accurately modelled using an Orowan approximation for slip rate. However, as deformation progresses, dislocation pile-up become pronounced within the g channels, further increasing the material resistance to deformation by effectively increasing the activation volume needed to initiate slip. It is speculated that the pile-up of dislocation in the g channels may be accounted for by the evolution and saturation of geometrically necessary dislocations (GNDs). Such effects are difficult to account for without exact modelling of crystal morphology and volume fraction of precipitate within the material matrix subjected to thermal and mechanical loading environments.

Multiscale modelling is achieved by means of communicating data between a continuum finite element model (FEM) and one of a representative volume element (RVE) of the CMSX4 microstructure. The outcome of this study contributed to the understanding of the deformation processes involved in super-alloys that ultimately results in greater accuracy in the design of components manufactured from this material.