Computer simulation of the initial rafting process of a nickel-base single-crystal superalloy

Rafting of the gamma/gamma' morphology of nickel-base superalloys is a well -known phenomenon during high-temperature deformation. The initial stages o f this type of directional coarsening were modeled two-dimensionally by the method of finite elements (FEs) using an energy-perturbation approach. In addition to the elastic energy density, the effect of the local difference of the hydrostatic stresses in gamma and gamma' in combination with the dif ferent lattice parameters of the two phases was considered in the calculati ons as a further driving force. From the results of modeling, the deformati on-induced internal stresses and strains were determined and used to evalua te the direction-dependent lattice parameters and lattice misfits of the tw o phases. The results agree well with experimentally determined values.