Influence of Zn on the microstructure and mechanical properties of Mg-Gd-Zr alloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 843; p. 143136
• Main Authors: Lei, Bin, Dong, Zhihua, Yang, Yan, Jiang, Bin, Yuan, Ming, Yang, Huabao, Wang, Qinghang, Huang, Guangsheng, Song, Jiangfeng, Zhang, Dingfei, Pan, Fusheng
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 23.05.2022; Elsevier BV
• Subjects: Chemical precipitation; Coherence; Ductility; Elongation; Extrusion; Gadolinium; Grain refinement; Grain size; Magnesium; Mechanical properties; Mg-Gd-Zr alloy; Microstructure; Orientation relationship; Precipitates; Texture; Zinc base alloys; Zirconium base alloys; Zn alloying; Mg-Gd-Zr alloy; Orientation relationship; Microstructure; Zn alloying
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2022.143136

Here, the microstructure and mechanical properties are investigated for the designed Mg-4Gd-0.5Zr-xZn (x = 0, 0.2, 0.5, 1.0 and 1.5 wt%) alloys with special emphasis on the effect of Zn. The results show that the designed Mg-4Gd-0.5Zr-xZn alloys exhibit the exceptional ductility. Among them, the Mg-4Gd-0.5Zr-1.0Zn and Mg-4Gd-0.5Zr-1.5Zn alloys show the elongation to fracture as high as 35.2% and 32.5%. Furthermore, a good strength-ductility balance is achieved in the alloys, which is basically ascribed to the grain refinement, texture softening and the precipitation of Zn-containing second phases. As Zn content increases from 0 to 1.5 wt%, the grain sizes of the extruded Mg-Gd-Zr-Zn alloys decrease from 6.02 to 3.05 μm, while the maximum texture intensity decreases from 11.13 to 5.24 m.r.d. Moreover, the Zn2Zr3 and Mg3Zn3Gd2 precipitates, which exhibit the completely coherent and semi-coherent orientation relationship with Mg matrix, are induced by the addition of Zn. These coherent and semi-coherent precipitates lead to noticeable strengthening effect and are not easy to become the source of crack, contributing to the high ductility in Mg-4Gd-0.5Zr-1.0Zn and Mg-4Gd-0.5Zr-1.5Zn. •The designed Mg-4Gd-0.5Zr-xZn (x = 0, 0.2, 0.5, 1.0 and 1.5 wt%) alloys all exhibit the exceptional ductility.•The Mg-4Gd-0.5Zr-1.0Zn and Mg-4Gd-0.5Zr-1.5Zn alloys exhibit a good strength-ductility balance.•The orientation relationship between the precipitates and Mg matrix was studied.