.7050 Aluminum Alloy Forging Process Of Dynamic Recrystallization Of Cellular Automata Simulation

The prediction and control of microstructure evolution in work piece during forging play an important role in design of forging process. With the developments of computational materials science, more and more quantitative investigation manners will be adopted rather than qualitative investigation manners in the research of microstructure evolution. Cellular automaton (CA) is an idealization model of complicated system, which is particularly suit to deal with the problems that are difficult to describe quantitatively. It has been applied in many science fields. In the material forming field, this method is extremely outstanding in simulating microstructure evolvement. However, the developed CA model has only investigated qualitatively without considering influences of grain topology deformation and coupling deformation parameters and exact forging.Combined with fundamental theory of physical metallurgy and experimental results, 2D multi-scale simulation platform of forging process was established using CA method. Dynamic recrystallization(DRX) behavior of aluminum alloy 7050 during hot forging process was simulated using the developed platform. The main contents of this text are as follows:The thermo-compression experiments were conducted with Gleeble-1500 machine to study the DRX behavior and rheological regularity of aluminum alloy 7050 under different conditions of temperatures and strain rates. Experimental results show that lower Z do good to DRX of aluminum alloy 7050, and size of R-grains are about 10～20μm. Based on dislocation mechanism and experimental results, DRX models, such as model of flow stress, model of dislocation density, model of DRX nucleation and growth, were established.A series of key technologies for DRX simulation, such as initial microstructure generating, simulation of microstructure evolvement, simulation of grain deformation, statistical calculating of microstructure characteristic and emulating with visual images, were studied in detail using CA. Coupling the DEFORM 3D simulation, a multi-scale simulation platform of forging based on CA was established using mixed programming of Visual Basic and Visual Fortran.Forging process for bulkhead forging of 7050 aluminum alloy was studied using simulation platform, and influences of deformation parameters on microstructure evolution of forging were simulated. The simulation results reflect DRX rules of 7050 aluminum alloy correctly. Then, the CA model was remanded with microstructure of free forging. Test results show that the proposed CA model coupling with FEM and grain topology deformation can reflect internal microstructure evolution of industrial forging exactly. In the end, die forging process was simulated using the developed simulation platform, it provided forging process design with theoretical guidance.