Study Of Grain Refinement, Hot Deformation Behavior And Working Technology Of Mg-Al Alloys

Magnesium alloys have great predominance for the applications of aerospace, automobile and electronics due to their high physical and mechanical properties. Compared with die-casting magnesium alloys, wrought magnesium alloys with higher strength, ductibility and diversified mechanical properties, can be satisfied with the requirement acting as structural parts. At present, the application investigation of wrought magnesium alloys is in a primary stage, the production cost of wrought magnesium alloys'goods is high and the correlative deformation technologies of wrought magnesium alloys are not mature.The study concentrates on the low coat commercial AZ31 alloy and the development of wrought magnesium alloys with good deformability, through grain refinement of Mg-Al series alloys in order to improve the deformability ulteriorly. Based on the investigation of hot deformation behavior, the magnesium alloy tubes with good comprehensive mechanical properties are obtained by controlling the microstructures during the extrusion processing of Mg-Al series alloys.In this paper, optical microscopy (OM), X-ray diffractometer (XRD) and scanning electron microscopy (SEM) have been used to analysis the experimental results. A low cost and higher room temperature elongation Mg-Al wrought magnesium alloy– AM30 alloy was obtained through orthogonal test by adjusting Al, Zn and Mn contents in the Mg-Al series wrought magnesium alloy. The effects of Ti and Sr on the microstructures and mechanical properties of AZ31 and AM30 alloys and the mechanism of grain refinement by Ti and Sr were investigated. Also the effects of low frequency electromagnetic casting (LFEC) parameters (Frequency and Current) on the microstructures and mechanical properties of AZ31 and AM30 alloys were investigated, the AZ31 and AM30 alloys'billets with a diameter of 100mm having finer grain size (<50μm) and uniform grain distribution were prepared successfully. The flow stress-strain curves of as-cast LFEC-ed AZ31 and AM30 alloys were obtained by using isothermal hot compressive test, combining the constitutive equation and dynamic materials model (DMM), the extrusion limit diagrams and...