Simultaneous improvement of strength and ductility by Mn addition in extruded Mg-Gd-Zn alloy
(1. School of Mechanical and Electrical Engineering, Hunan City University, Yiyang 413002, China;
2. State Key Laboratory of Mechanical Transmissions, College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
3. College of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China)
2. State Key Laboratory of Mechanical Transmissions, College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
3. College of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China)
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.
Key words: Mg-Gd-Zn alloy; Mn addition; microstructure; mechanical properties