Simultaneous improvement of strength and ductility by Mn addition in extruded Mg–Gd–Zn alloy
Jun Zhao, Bin Jiang, Yan Song, Zuocai Dai, Liwei Lu, Chao He, Guangsheng Huang, Ding-fei ZHANG, Fusheng Pan
Abstract
The influence of Mn content on the microstructure, tensile properties and strain-hardening behaviors of extruded Mg−1Gd−0.5Zn−xMn (x=0, 0.3 and 1, wt.%) alloy sheets was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), and electron backscatter diffraction (EBSD). The results show that the completely recrystallized grain structure and the extrusion direction (ED)-titling texture are observed in all the extruded sheets. The mean grain size and weakened ED-titling texture of the extruded sheets are gradually reduced with increasing Mn content. This is primarily associated with the formation of new fine α-Mn particles by Mn addition. Tensile properties show that the addition of Mn also leads to the improvement of yield strengths, ultimate tensile strengths and elongations of the extruded Mg−1Gd−0.5Zn−xMn sheets, which is mainly due to the fine grains and α-Mn particles. In addition, the Mg−1Gd−0.5Zn−1Mn sheet has the lowest strain-hardening exponent and the best hardening capacity among all prepared Mg−1Gd−0.5Zn−xMn sheets.