Classify phase transformations in the context of thermodynamics, mechanism and structure. Explain solution theory based on mixing of components and phase separation. Discreminate types of solid solutions and phases; interstitial and primary substitutional solutions, intermediate phases, electron and size factor compounds and ordered phases. Explain the kinetic and thermodynamic principles of solid state phase transformations such as spinodal decomposition, order-disorder, precipitation, eutectoid and martensitic transformations.