Dislocation Density-Based Constitutive Model and Processing Map for T2 Copper During Isothermal and Time-Variant Deformation

Isothermal compression tests were carried out to study the hot deformation behavior of T2 copper under various conditions. The deformation parameters, such as temperature and strain rate, have strong influence on flow stress and microstructure evolution of the alloy. A unified dislocation density-based model considering dynamic recovery and recrystallization was established. And material parameters of the developed model were optimized by genetic algorithm. Comparisons between the experimental and model data demonstrates that the developed model can precisely describe the flow behavior at quite wide range of deformation conditions. Meanwhile, the designed iterative procedure allows the model to be applied in time-variant deformation conditions. Processing map and microstructure examination were constructed to optimize the processing window of the studied alloy. According to the processing maps, flow instability mainly appeared at low temperatures of 500–650 °C and strain rates higher than 0.1 s⁻¹. The optimum deformation parameters of T2 copper was concluded as the temperature range of 700–800 °C and the strain rate of 0.1–1 s⁻¹.