织构与晶粒对挤锻复合成形AZ61镁合金力学性能的影响

Effect of Texture and Grain Size on Mechanical Properties of AZ61 Magnesium Alloy during Close-Die Hot-Pressing of Extruded Performs

采用AZ61镁合金挤压态预成形坯材,通过不同变形程度的模锻成形试验制备AZ61镁合金拉伸试样,运用金相观察、电子背散射衍射(EBSD)取向成像技术,分析了AZ61镁合金在挤锻复合成形过程中晶粒尺寸与织构对其室温力学性能的影响。结果表明,挤压态预成形试样存在强烈的基面织构,晶粒处于硬取向,基面滑移难以启动,AZ61镁合金具有较高的屈服强度。在基面织构强度相似的情况下,晶粒细化可提高试样的屈服强度和伸长率,但不能通过变形的无限增加改善合金的组织与性能。

Using AZ61 extruded performs,tensile specimens of AZ61 magnesium alloy were fabricated by close-die hot pressing with varied deformation rate.Effects of grain size and texture during close-die hotpressing process on ambient mechanical properties of the alloy specimens were analyzed by OM,EBSD.The results reveal that intense basic texture can be observed in the extruded performs,and the grain is located at hard orientation,so it is difficult to slide up,taking the high yield strength.Under the condition of the similar primary texture intensity,grain refinement can improve the yield strength and elongation of the alloy specimens,however,deformation rate is limited for improving the microstructure and properties of the alloy specimens.