Multi-Scale Modeling And FE Simulation During High Temperature Deformation Of The Titanium Alloys

With the application of recent achievements of numerical method, computer technology and materials processing theory, the plastic deformation processes can be simulated, and the final microstructure, mechanical properties and service qualities of workpiece can be predicted, which will be beneficial to the transition from skill to science and make its improvement to be possible in hot forming.During high temperature deformation, both deformation behavior and microstructure undergo a series of dynamic changes and the microstructure evolution will influence the flow behavior of materials. Coupled simulation of deformation behavior, heat transfer and microstructure evolution is based on the understanding of an interaction between the deformation behavior and the microstructure evolution. Applying the multi-scale models to the process simulation of high temperature deformation, it is scientific foundation for the understanding of deformation mechanism and optimizing the process parameters and improving the service qualities of workpiece.The relationship between the microstructure evolution with the deformation parameters has been investigated based on the high temperature deformation mechanism of metals. And, the microstructure evolution models have been established through the dislocation density rate as an internal state variable. Meanwhile, the models are examined by experimental results of a TC6 titanium alloy. The comparison of the predicted results with the experimental data shows that the microstructure evolution models are stable and reliable.A set of mechanisms-based constitutive equations have been proposed based on the mechanism of dislocation strengthening and grain boundary strengthening, in which the contributions of different mechanisms and individual phase to the deformation behavior have been analyzed and the interaction between the microstructure evolution and deformation process have been revealed. Meanwhile, the...