Research On Microstructure Evolution Of AZ80+Ce Magnesium Alloy During Wheel Forming Process And Simulation Optimization

The performance of the hub depends on the microstructure evolution and the final microstructure of the multi pass forming process. This paper takes the AZ80+0.4%Ce magnesium alloy wheel as the research object, Intercepting sample in the different parts of cast bar, upsetting blank, punching preform, anti extrusion molding and the final molding.with optical microscope and scanning electron microscope(SEM), The microstructure morphology and distribution characteristics of the blank in each stage were analyzed.In order to optimize the process and process parameters, it can improve the microstructure of the wheel hub and provide a reference for the improvement of the performance. Magnesium alloy wheels in the automotive industry has an important guiding significance for the wide range of applications. The main conclusions are obtained in this study:(1) Microstructure of AZ80+0.4%Ce magnesium alloy includes α-Mg, β-Mg17Al12,Al8Mn5 and Al4 Ce. By comparing the casting microstructure of AZ80 can be seen. Theβ-Mg17Al12 phase is changed from a continuous network structure to a small island or a small granular form. The newly formed needle like Al4 Ce phase is distributed in the grain and grain boundaries.(2) By comparing the AZ80 squeezing state organization can be seen, AZ80+0.4%Ce magnesium alloy grain is small and relatively uniform, the second phase precipitation less;Along the extrusion direction, the broken Al4 Ce phase can be seen at the grain boundaries.The continuous precipitation of β-Mg17Al12 phase was inhibited by Al4 Ce phase.(3) The microstructure of upsetting is extremely uneven, dynamic recrystallization grain is small, the size is about 5.26μm;there are residues of coarse grains,the size is about 60μm.After each stage of the organization are relatively homogeneous,the size is about 26 μm.Due to the large middle heating times, the molding wheel rim in grain tended to grow up.(4) Compared with the AZ80 hub, the performance of AZ80+0.4%Ce wheel is greatly improved. Part of the hub wall in tensile strength reaches 340 MPa, spoke part strength reached 315 MPa.Elongation is the highest in the middle of the wheel, reaching 10%.Finally,according to the microstructure evolution law and the problems in the test of magnesium alloy wheel. Reducing the process of extrusion,and changing the wall thickness and the hub flange.And using Deform to simulate and optimize it.This lays the foundation for the further wheel test, and provides the theoretical guidance.