Numerical Simulation Of Hot Deformation Physical Process Of Magnesium-lithium Alloys Of Mg-5.21%Li-3.44%Zn-0.32%Y-0.01%Zr

Magnesium-lithium alloys are called super light alloy, and have certain applications in engineering due to its super light characteristic. The join of lithium improves the plastic deformation ability of magnesium alloy to a certain extent, but it is lesser to discuss hot deformation process and mechanism of magnesium-lithium alloys, this paper discusses constitutive relationship and changes of crystallite size of material in hot deformation process of magnesium-lithium alloys combining with physical simulation and various numerical methods.The physical simulation performed hot compression test to a kind of magnesium-lithium alloys using Gleeble-1500 thermal simulation testing machine under the condition of real strain was 1 choosing 250℃,300℃,350℃and 400℃four deformation temperatures and 0.001 s-1,0.01 s-1,0.1 s-1,Is-1,and 10-1 five strain rates.Thermal deformation constitutive relationship of alloy based on the physical simulation data of thermal deformation, the methods of establishment were respectively regression analysis and artificial neural networks. Through the establishment of constitutive relationship confirmed the relationship of deformation activation energy, critical strain of magnesium-lithium alloys and Z parameters. The constitutive relationship illustrated the deformation of alloy was dynamic recrystallization type under the condition of choosing deformation, the obtained constitutive equation and results predicted by artificial neural network can reflect the stress-strain relationship of material well. The constitutive equation has more clear description for the relationships between each parameter in material processing, while neural network model has a higher accuracy.Critical strain and recrystallization size mathematical model of material established according to the experimental data and hot-working theory. Finite element model established based on finite element software Marc through the secondary development on the bases of model, and the temperature field and stress strain field particularly the changes of crystallite size of the alloy in hot compress were simulated and compared with metallographic examination results, the results show that the simulation results are in good agreement with the experimental results.