Dynamic Recrystallization Simulation Of GH4169 Alloy During Thermal Deformation

Because of its excellent mechanical and material performance, GH4169 alloy has an extremely wide range of applications in the aerospace, petroleum and nuclear industry. It also has a character that the crystal organization of GH4169 alloy is particularly sensitive to heat during its production. That is also why mastering the comprehensive relationship between microstructure evolution and the process parameters during thermal deformation has a significant value when optimizing the properties of the alloy and establishing reasonable procedures for the different requirements of the process.With the development of material science and computer technology, a large number of models that can describe the material microstructure evolution has emerged. Two typical types are Empirical model and Cellular Automata (CA) model. Empirical model can ensure the accuracy of the simulation in a certain range and incorporating with economic finite element method (FEM) software. CA has a great advantage when simulating complex systems, so it has received more and more attentions of academia.However, for GH4169 alloy, few empirical models have been applied in microstructure evolution simulation. Especially, there is almost no cellular automata model has been introduced. Therefore, numerical simulation of the GH4169 alloy microstructure evolution has great theoretical and practical significance to predict and control the performance of GH4169 alloy.Considering dynamic recrystallization is a major evolution process in thermal deformation process of GH4169 alloy, this paper has simulated this dynamic recrystallization by using two different models. And the structure is as follows:Firstly, the hot compression tests of GH4169 alloy were performed on the MMS-300 machine to obtain the flow stress curves under different temperatures and strain rates. In accordance with its flow stress data, a high-temperature constitutive equations and empirical model of microstructure evolution of alloy GH4169 is calculated.Secondly, by embedding secondary development subroutine (in FORTRAN language) into finite element software DEFORM-3D, the dynamic recrystallization of alloy GH4169 has been introduced in this simulation. The simulation results agree well with the kinetics of dynamic recrystallization of classical theory and physical experiments.Then, a set of CA methods have been developed for dynamic recrystallization of GH4169 alloy base on phenomenological theory. Combined with the effective strain rates data which simulated by DEFORM-3D, the CA method has numerically calculated thermal deformation process, coupling with the constantly changing strain rates. The result will be closer to the actual situation and the accuracy of the simulation will be increased.In this paper, the computer simulation technology been successfully applied in simulating dynamic recrystallization of GH4169 alloy through the CA method and secondary development for DEFORM-3D. The results show good agreement with those of experiments and have certain practical values.