STEADY-STATES AND MICROSTRUCTURAL EVOLUTIONS IN DRIVEN SYSTEMS

There are many cases of practical interest where ordered intermetallic compounds or concentrated alloys are maintained in non-equilibrium co nditions by some external dynamical forcing : such is the case for all oys under irradiation, under high energy ball milling or under cyclic fatigue. Phase equilibria in such systems cannot be assessed from equi librium thermodynamics. We briefly review here different approaches ba sed on kinetic descriptions for handling the question of phase stabili ty in these systems, and showing that these methods are also appropria te for following diffusion-controlled microstructural evolutions in sy stems, either sustained in a non-equilibrium state or during a relaxat ion toward an equilibrium state.