Dynamic recrystallization behavior of AZ31 magnesium alloy processed by alternate forward extrusion  

作　　者：Feng LI Yang LIU Xu-Bo LI 

机构地区：[1]School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China

出　　处：《Frontiers of Materials Science》2017年第3期296-305,共10页材料学前沿（英文版）

基　　金：Acknowledgement This project was supported by the National Natural Science Foundation of China （Grant No. 51675143）.

摘　　要：One of the important factors that affect the microstructure and properties of extruded products is recrystallization behavior. Alternate forward extrusion （AFE） is a new type of metal extrusion process with strong potential. In this paper, we carried out the AFE process experiments of as-cast AZ31 magnesium alloy and obtained extrusion bar whose microstructure and deformation mechanism were analyzed by means of optical microscopy, electron backscattered diffraction and transmission electron microscopy. The experimental results indicated that homogeneous fine-grained structure with mean grain size of 3.91 pm was obtained after AFE at 573 K. The dominant reason of grain refinement was considered the dynamic recrystallization （DRX） induced by strain localization and shear plastic deformation. In the 573-673 K range, the yield strength, tensile strength and elongation of the composite mechanical properties are reduced accordingly with the increase of the forming temperature. Shown as in relevant statistics, the proportion of the large-angle grain boundaries decreased significantly. The above results provide an important scientific basis of the scheme formulation and active control on microstructure and property for AZ31 magnesium alloy AFE process.One of the important factors that affect the microstructure and properties of extruded products is recrystallization behavior. Alternate forward extrusion （AFE） is a new type of metal extrusion process with strong potential. In this paper, we carried out the AFE process experiments of as-cast AZ31 magnesium alloy and obtained extrusion bar whose microstructure and deformation mechanism were analyzed by means of optical microscopy, electron backscattered diffraction and transmission electron microscopy. The experimental results indicated that homogeneous fine-grained structure with mean grain size of 3.91 pm was obtained after AFE at 573 K. The dominant reason of grain refinement was considered the dynamic recrystallization （DRX） induced by strain localization and shear plastic deformation. In the 573-673 K range, the yield strength, tensile strength and elongation of the composite mechanical properties are reduced accordingly with the increase of the forming temperature. Shown as in relevant statistics, the proportion of the large-angle grain boundaries decreased significantly. The above results provide an important scientific basis of the scheme formulation and active control on microstructure and property for AZ31 magnesium alloy AFE process.

关 键 词：magnesium alloy alternate forward extrusion （AFE） mechanical property dynamic recrystallization 

分 类 号：TG146.22[一般工业技术—材料科学与工程] U465.11[金属学及工艺—金属材料]