Modeling dislocation evolution around precipitates in superalloy

In this paper we discuss a new approach to correlate the dynamic mechanical properties of Nickel based superalloys to their precipitate driven mechanism of dislocation evolution. These precipitates are responsible for arresting defects or dislocations and enhancing the life of a structural component. The mechanism of dislocation evolution across grain or phase boundaries give complex patterns whose initial stages can be correlated to strain rate dependent damping parameters. We show here molecular dynamic simulation of dislocation evolution under cyclic loading of Ni3Al precipitates in Ni matrix and make an attempt to relate the growth rate parameters to the size of the precipitate and damping constants. The mechanism of deformation under cyclic normal and shear loading are investigated. This is an ongoing effort to extend our understanding to more complex and realistic situation involving temperature effects and microstructure of the superalloys.