Chapter 6 - Solid Solutions

Abstract

A solid phase containing two or more kinds of atoms, the relative proportions of which may be varied within limits, is described as a solid solution. Terminal solid solutions are based on the structures of the component metals; intermediate solid solutions may have structures that are different from any of those of the constituents. Most solid solutions are of the substitutional type, in which the different atoms are distributed over one or more sets of common sites, and may interchange positions on the sites. In interstitial solutions, the solute atoms occupy sites in the spaces between the positions of the atoms of the solvent metal, this can only happen when the solute atoms are much smaller than the atoms of the solvent. In addition to this, the chapter indicates that in the the ideal solution, the thermal partition function is determined only by the number of atoms of each kind present, and the configurational partition function corresponds to a completely random distribution of the atoms.