The Austenite Decomposition interface () is found under the Heat Transfer>Metal Processing () branch when adding a physics interface. The physics interface is intended for studying metallurgical phase transformations. You can use this interface to study diffusional, displacive, and user-defined (solid-solid) phase transformations. Physical phenomena, such as latent heat of phase transformation and transformation strains can be computed and used in Heat Transfer in Solids and Solid Mechanics. With the Nonlinear Structural Materials Module or the Geomechanics Module, plastic strains and hardening behavior of each metallurgical phase can be used in Solid Mechanics.

This interface is based on the Metal Phase Transformation interface. This chapter will only describe the nodes and settings that set the Austenite Decomposition interface apart from the Metal Phase Transformation interface. With regard to other settings at the physics interface level and feature level, see The Metal Phase Transformation Interface.

When the Austenite Decomposition interface is added, nine nodes are added to the Model Builder — five Metallurgical Phase nodes and four Phase Transformation nodes. The interface is tailored specifically to the decomposition of austenite into a combination of ferrite, pearlite, bainite, and martensite. The phase nodes are given names to reflect this:

The Initial Phase Fraction is set to one in the Austenite node, and zero in the other metallurgical phase nodes. Four Phase Transformation nodes are also created to define the relevant phase transformations:

The source and destination phases in each phase transformation are set to the corresponding phases that have been created. The Phase transformation model is set to Leblond–Devaux with General coefficients, except in Austenite to Martensite, where it is set to Koistinen–Marburger.

From the Physics toolbar, you can delete or disable metallurgical phases and phase transformations that are irrelevant in a given situation, and you can add additional metallurgical phases and phase transformations. You can also right-click Austenite Decomposition to select physics features from the context menu.

The Label is the default physics interface name.

The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.

The default Name (for the first physics interface in the model) is audc.