| The purpose of this paper is to examine the thermal compression behavior, extrusionforming property of AZ80magnesium alloy under different deformation conditions, and tosimulate the microstructure evolution in the extrusion forming and magnesium alloy wheelhub initial forging, thus supplying the basis for the development and application of plastictechnology of Mg alloy.The thermal compression behavior of AZ80magnesium alloy was researched withthe temperature from250℃to400℃and strain rate from0.0005s-1to0.002s-1toanalysis the influence of forming temperature, strain rate and strain to the thermalcompression rheological stress of AZ80Mg alloy, and obtain a rheological equation ofstate that is more suitable to AZ80magnesium alloy.AZ80was isothermally extruded by the designed moulds with the temperature from300℃to400℃and extrusion ratios from4:1to16:1. Microstructure examination wasconducted to observe the Mg alloy specimens before and after the extrusion. Analysis andcomparison shows that grains inside the alloy was Significantly refined after the thermalextrusion,and the size in center portion is bigger than that in the brim portion. Grain sizeincreases with the increasing of the extrusion temperature, and decreases with the rising ofthe extrusion ratio.With Yada model which is amended, the change of grain size of AZ80in theextrusion forming process was simulated by a finite element software called MARC,which is basically consistent with the experiment results. At the same time the validity ofthe Yada model was demonstrated.With Yada model of finite element software Marc, the change of grain size at thebeginning of AZ80magnesium alloy wheel hub forging process was simulated. Thesimulation effectively reflect the microstructure evolution at the beginning of AZ80magnesium alloy forging process. concluded. This result demonstrated the validity of theYada model again. |
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