A general model describing flow stress of copper alloys in different deformation conditions

A general model describing flow stress as a function of internal state of materials and such deformation conditions as temperature, strain, strain rate, sudden changes of temperature and strain rate as well as time intervals in deformation process is presented in the paper. The model describes strain hardening as well as softening processes taking place during deformation defined as dynamic softening and during interval or after deformation defined as static softening. The model was developed on the basis of internal state fundamental function that is completed with the modified Garofalo equation describing internal state characteristic level, characteristic strain values related to the Zener–Hollomon parameter, kinetics of dynamic and static softening processes, and reaction of materials to slow and sudden changes in strain rate and temperature. The model can be used in numerical simulation and design of metal forming processes.