  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 and an orientation parameter 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 these two parameters. The model is used to
describe the stress orientation of hydrides in Zr-alloys in light of
experiments.
