Equilibrium Phase Diagrams
Joseph Datsko · 2020
Equilibrium phase diagrams are graphs that indicate which phases exist at any specific combination of temperature, pressure, and composition for a given material. Phase diagrams are classified as unary, binary, ternary, etc., on the basis of the number of pure components involved. A phase is a chemically homogeneous, physically distinct, and mechanically separable portion of a material system. The chapter discusses examples of the most common types of phase diagrams, such as those having eutectics or eutectoids or those of age-hardenable alloys. The pure elemental metal, lead, for example, is a single solid phase at room temperature. Heat is either absorbed or liberated during a phase transformation, depending upon the phase change involved. A binary phase diagram is a graph of a two component material system that shows the following for any combination of temperatures and original composition: the phases that are present; the composition of each phase; the amount of each phase present.