Mg-Al-RE系镁合金组织与性能

Microstructures and mechanical properties of Mg-Al-RE alloys

通过铸造和挤压变形工艺,研究了AE(Mg-Al-RE)系合金的显微组织及稀土和铝含量的变化对AE系合金显微组织和力学性能的影响.实验结果表明:AE系合金的铸态显微组织由α-Mg基体相和沿晶界分布的Al4RE,Mg17Al12相组成.随着稀土含量的增加,Mg17Al12相逐渐消失,Al4RE相的体积分数增加,并逐渐沿晶界处形成连续网状结构.挤压实验结果显示:AE系合金具有良好的形变加工性能,挤压后合金的强度和塑性均比铸态合金大幅度提高.稀土元素的加入对合金形变过程中的动态再结晶有一定的抑制作用.在AE系稀土镁合金中增加Al含量,可以使合金的综合力学性能上升到一个较高的水平.

The effects of Al and RE（misch metals） contents on microstructures and mechanical properties of AE（Mg-Al-RE） series alloys are studied by the processes of casting and extrusion deformation.The results show that the as-cast microstructures of AE alloys consist of α-Mg matrix and intermetallic compounds Al4RE and Mg17Al12,distributed in grain boundaries.With the increase in RE content,the Mg17Al12 phase disappears and the volume fraction of Al4RE increases,which forms a continuous network in the grain boundaries.Processing of hot extrusion performed on AE alloys reveals that they have good deformability and both the strength and the ductility of the alloys increase greatly after extrusion.RE restrains the dynamic recrystallization occurring during extrusion and the increase of Al concentration improves greatly the mechanical properties of the alloys at room temperature.