挤压速度和电磁铸造锭坯对AZ31镁合金板材组织和性能影响

文章研究挤压条件下挤压速度和电磁铸造锭坯对挤压态AZ31镁合金板材组织和性能的影响。研究结果发现,挤压速度比较低时,板材晶粒尺寸小,板材的表面质量比较好;随着挤压速度的降低,抗拉强度、屈服强度和延伸率都有一定的提高。由于镁合金是HCP的晶体结构,同时对挤压速度非常敏感,对变形均匀性影响比较大,因此造成挤压板材的内外晶粒大小不均。在电磁场的作用下,溶质在晶内的固溶度增大,同时晶粒大小也比常规铸造的细小,因此电磁铸造的锭坯经挤压机挤压后,挤压板材的晶粒尺寸比较细小,且强度和塑性都有所提高。

Effects of extrusion speed and billets of electromagnetic casting on microstructure and mechanical properties of AZ31 magnesium alloy sheet

The effects of extrusion speed and ingots of electromagnetic casting on microstructure and mechanical properties of AZ31 magnesium alloy extrusions are investigated.When extrusion speed is lower,grain size of the extrusion decreases and surface quality in extrusion AZ31 magnesium alloy is very good.As a result,the tensile or yield strength and elongation of the extrusion decreases with the extrusion speed's increasing.Magnesium alloys are hexagonal closed-packed(HCP) and very susceptible to extrusion speed.And they have a significant effect on deformation uniformity,so gain sizes on the surface and in the center of the extruded AZ31 sheet are non-uniform.Electromagnetic field during DC casting can significantly increase the solute content in grains and can fine microstructures in ingots of AZ31 magnesium alloy,so the extruded sheet made of electromagnetic casting ingots has finer grain size,higher strength and higher elongation than the one made of DC casting ingots.