| The purpose of this paper is to examine the uniaxial tensile behavior, extrusionforming propertie and the microstructure evolution in the extrusion forming of castingAM60magnesium alloy under different deformation conditions, and to simulate themicrostructure evolution in the extrusion forming, thus supplying the basis for thedevelopment and application of plascic technology of Mg alloy.The uniaxial tensile behavior of casting AM60magnesium alloy was researched withthe temperature from250℃to400℃and strain rate from0.0005s-1to0.05s-1to analysisthe influence of forming temperature, strain rate and strain to the rheological stressofAM60Mg alloy. The vule of thermal deformation activation energy—Q was calculatedand obtain a rheological equation of state that is more suitable to the casting AM60magnesium alloy.Casting AM60was extruded by the designed moulds with the temperature from300℃to400℃, extrusion speed from10mm/s to20mm/s and extrusion ratios from4:1to16:1. Not only was the microstructure of cast AM60Magnesium alloy observed, but alsothat of extrusion specimens. The grain size of forming specimens is different for differentzone, and the size in center portion is bigger than that in the brim portion. Grain sizeincreases with the increasing of the extrusion temperature, and with the extrusion ratioincreasing the grain size decreases. The effect of extrusion speed to the grain size is notobvious, but can affect the uniformity of microstructure distribution, the grain size willbecome more disorderly with accelerating. And the degree of order of effect of grain sizeafter the isothermal extrusion was determined among the extrusion temperature, extrusionspeed and extrusion ratio by orthogonal test.With Yada model which is amended, the change of grain size of AM60in theextrusion forming process was simulated by a finite element soft ware called MARC,which is basically consistent with the experiment results. |
PDF Full Text Request