Part III describes the important and established families of phase transitions in materials. Chapters 10–16 describe structural and chemical phase transformations of materials that occur by movements of atoms. These include heterogeneous first-order transitions such as melting and precipitation, and spinodal decomposition and ordering that may occur homogeneously as second-order phase transitions. Martensite and other displacive phase transitions are the subject of Chapter 15, and microstructural and nanostructural aspects of phase transformations are covered in Chapter 16. All these phase transitions involving atom rearrangements are historical figures in the field of materials science, and new phenomena are often explained with reference to them.

Chapter 17 describes some of the major phase transitions involving electrons and spins that occur inside materials. Electronic and magnetic phase transitions can sometimes be understood with similar approaches as phase transformations involving atom rearrangements, but some aspects of electronic or magnetic excitations are not classical. This is emphasized in Chapter 18, which ends by touching on quantum criticality. Research on quantum phenomena such as superconductivity is often reliant on controlling the structures of materials. Likewise, results from condensed matter physics offer new insights into phase transformations in materials.