Stress orientation of second-phase in alloys: Hydrides in zirconium alloys

A model for precipitation of the plate-shaped second-phase under applied stress is presented. The precipitates in the matrix-precipitate system are represented by their local volume fraction ζ and an orientation parameter θ that defines the alignment of a precipitate platelet in a given direction. Kinetic equations, based on diffusion theory and classical nucleation theory, are used to describe the time evolution of ζ and θ . The model is used to describe the stress orientation of hydrides in Zr-alloys in light of experiments.