The Austenite Decomposition interface is a specialized interface that considers hardening of steel from an austenitic state. During hardening of steels, the material is heated above the austenitizing temperature. It is then cooled, and depending on the rate of cooling, a combination of destination phases such as ferrite, pearlite, bainite, and martensite can form. The Austenite Decomposition interface automatically creates corresponding Phase nodes and Phase Transformation nodes. You can also define an arbitrary number of additional phases and phase transformations. Optionally, you can define your own phase transformation models and let them coexist with other active phase transformations in the analysis. The Austenite Decomposition interface lets you generate a compound material whose properties are phase-composition-dependent. This material can be used by other physics interfaces, such as Solid Mechanics and Heat Transfer in Solids.