Place: International Conference on the Strength of Materials, Dresden, Germany
One set of constitute equations are built for Nickel-based superalloy single crystals which consider the FCC dislocation sliding in superalloy matrix channel, screw and mixed FCC dislocations depositing in gamma-gamma prime phase boundaries, L12 super-dislocation nucleation by pairs of FCC deposited dislocations and precipitate cutting by L12 super-dislocations. In order to push the constitutive model to FEM application the superalloy microstructure is simplified to one unit cell which includes 3 volume fractions for FCC matrix channel and one volume fraction for the precipitate. The local stresses are calculated for every volume fraction which are functions of external stress, misfit ratio between matrix and precipitate, deposited FCC dislocation densities, and unit cell configureations. Furthermore through minimize the Gibs free energy of the unit cell creep mechanism change when unit cell configuration changes rafting creep mechanism can be considered. Creep behaviours of superalloy single crystal among wide range of temperatures are modelled and compared with relative experiments for CMSX-4 to evaluate the constitutive models.