The Effect of Y/Er and Zn Addition on the Microstructure and Mechanical Properties of Mg-11Li Alloy

Mingquan Zhang; Jinghuai Zhang; Ruizhi Wu; Hongwei Cui; Ertuan Zhao; Shujuan Liu; Pengfei Qin; Qing Ji

doi:10.3390/ma12193066

The Effect of Y/Er and Zn Addition on the Microstructure and Mechanical Properties of Mg-11Li Alloy

Materials (Basel). 2019 Sep 20;12(19):3066. doi: 10.3390/ma12193066.

Authors

Mingquan Zhang¹, Jinghuai Zhang², Ruizhi Wu³, Hongwei Cui⁴, Ertuan Zhao⁵, Shujuan Liu⁶, Pengfei Qin⁷, Qing Ji⁸

Affiliations

¹ Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. zmq1106435777@163.com.
² Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. zhangjinghuai@hrbeu.edu.cn.
³ Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. rzwu@hrbeu.edu.cn.
⁴ College of Materials Science and Engineering, Shandong University of Technology, Zibo 255000, China. chw@sdut.edu.cn.
⁵ School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China. etzhao@sdut.edu.cn.
⁶ Department of Materials Physics and Chemistry, Harbin Institute of Technology, Harbin 150001, China. liusj0817@hit.edu.cn.
⁷ Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. pfqin@ciac.ac.cn.
⁸ Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. jiqing@hrbeu.edu.cn.

Abstract

Although body-centered cubic (BCC) structural magnesium-lithium (Mg-Li) alloys have lower density and better formability than common hexagonal close-packed (HCP) Mg alloys, their applications remain limited due to their low strength. The purpose of this study is to investigate the effect of Y/Er and Zn addition on the microstructure and tensile properties of Mg-11Li alloy with a BCC structural matrix by comparing Mg-11Li, Mg-11Li-4Y-2Er-2Zn, and Mg-11Li-8Y-4Er-4Zn (wt %) alloys. The results indicate that the addition of Y/Er and Zn at a ratio of 3:1 cannot promote the formation of long-period stacking ordered structure in Mg-11Li alloy such as that in Mg-Y-Er-Zn alloys and the dominant intermetallic phases formed are BCC Mg₂₄RE₅ and face-centered cubic (FCC) Mg₃RE₂Zn₃ phases. With an increase of the content of Y/Er and Zn in an as-cast alloy, the fraction of intermetallic particles increases and the grain size decreases. The addition of Y/Er, as well as Zn, dramatically promotes the refinement of dynamic recrystallization (DRX) during extrusion. The initial intermetallic phases induced by Y/Er and Zn addition are broken into relatively fine particles during extrusion, and this contributes to refining the dynamic recrystallized (DRXed) grains mainly by the particle stimulated nucleation mechanism. The as-extruded Mg-11Li-4Y-2Er-2Zn and Mg-11Li-8Y-4Er-4Zn alloys exhibit much higher tensile strength as compared with as-extruded Mg-11Li alloy, which is mainly ascribed to the refined DRXed grains and numerous dispersed intermetallic phase particles. It is suggested that further refinement of intermetallic particles in these extruded Mg-11Li-based alloys may lead to higher quality alloy materials with low density and excellent mechanical properties.

Keywords: Mg-Li alloy; mechanical properties; microstructure; rare earth.

Abstract

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