Insight into Y Content on Microstructure and Mechanical Properties of Mg-Gd-Y-Zr Alloy

• Published in: Materials Vol. 18; no. 11; p. 2475
• Main Authors: Li, Yongfeng, Zhang, Ang, Li, Chuangming, Xie, Hecong, Hu, Hengrui, Gao, Yuyang, Cui, Yuhong, Dong, Zhihua, Li, Tian, Jiang, Bin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25.05.2025; MDPI
• Subjects: Alloys; Crystallography; Gadolinium; Grain boundaries; Grain size; High strength alloys; Magnesium; Mechanical properties; Microstructure; Nucleation; Oxidation; R&D; Research & development; Scanning electron microscopy; Specialty metals industry; Ultimate tensile strength; Zirconium; Zirconium alloys; Zirconium base alloys; Massachusetts; Japan; Mg alloy; microstructure evolution; Y content; mechanical properties
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma18112475

This paper investigates the effects of Y content on the microstructure and mechanical properties of Mg-9Gd-xY-0.5Zr alloys. The mechanical properties, together with the grain size, first increase and then decrease, exhibiting a non-monotonous change with the increase in Y content. The alloy with 3 wt.% Y exhibits the best mechanical properties compared to the Y free alloy, with an increase in ultimate tensile strength and yield strength of 33.4% and 19.2%, respectively. However, further increase in the Y content (5 wt.%) does not enhance the strength but promotes the growth of the Mg5(Gd,Y), becoming nucleation points and propagation paths for cracks, leading to a decrease in performance. The cubic phase REH2 and oxide are not the reasons for the poor ductility in as-cast Mg-9Gd-xY-0.5Zr alloys due to low content, and the crystallographic orientation relationship between REH2 and α-Mg is (220)REH2//(112¯0)Mg, and the interface mismatch is 9.13%. This paper systematically prepares and investigates the high-strength as-cast Mg-Gd-Y-Zr alloy, which has important guiding significance.