The evolution of solutions: A thermodynamic analysis of mechanical alloying

Normal thermodynamic theory for solutions begins with the mixing of component atoms. Many solutions are, however, prepared by mixing together lumps of the components, each of which might contain millions of identical atoms. We examine here the way in which a solution evolves from these large clusters of components, from-purely thermodynamic point of view. There are some interesting results, including the prediction that solution formation by the mechanical alloying of solid components cannot occur unless there is a gain incoherency as the particles become small. The nature of the barrier to mechanical alloying is discovered. There is also the possibility of a metastable state prior to the achievement of full solution, when the component atoms prefer like-neighbors.