Study On Microstructure And Properties Of ZK60Magnesium Alloy Produced By Sheet Extruding

Magnesium alloys are a potential structure material, having high specificstrength, good processability and recyclability, these advantages make it have astrong appeal for the transportation, the automotive and aerospace industry. however,the using of magnesium alloys is not as widely as expected, because of somedisadvantages, such as poor ductility, relatively low strength, poor creep resistanceand high temperature performance, these all due to their hexagonal close-packedcrystal. Studies have shown that, plastic deformation can effectively improve theductility of magnesium alloy at room temperature. On the existing plasticdeformation technologies, the strengthening effect more obvious and commontechnique is concentrated in extrusion deformation, however the shape of the existingextrusions are more concentrated in the bar.In this paper, basing on the extrusion tchnology, changing the shape of theextruded parts, the sheet extruding die was designed, which has a comprehensivecharacteristics with extruding and rolling deformation. After sheet extrudingdeformation, the sheet have a better performance because it have both extruding androlling performance, which is also the innovation of this paper.The die was used for ZK60magnesium alloys sheet extruding at differenttemperatures with330℃,350℃,370℃and390℃. Then the mechanicalproperties and grain refinement of ZK60magnesium alloys produced by sheetextruding at different temperatures were investigated through finite elementsimulation and experiment.Using DEFORM-3D to conduct finite element simulation, the results show thatthe changes of velocity field, temperature field and effective strain field during theprocessing of sheet extruding which can explain the evolution of the grain and thechange of mechanical properties.After sheet extruding, by optical microscopy to observe the change of the organization, the results show that the grain are refined obviously after sheetextruding.The grain size decreases first and then increases with the increasingtemperature, and reaches the minimum value at370℃.Using tensile testing toobtain the mechanical properties of ZK60magnesium alloy produced by sheetextruding, the results show that various peformance are all improved with theincreasing temperature， and when the temperature reach370℃, the bestcomprehensive performance is obtained.Based on the results of experiment and simulation, revealing the impact oftemperature on the microstructure and mechanical properties during the processingof sheet extruding.