J. Mater. Sci. Technol. ›› 2024, Vol. 184: 245-255.DOI: 10.1016/j.jmst.2023.10.019

• Research article • Previous Articles     Next Articles

Microstructural evolution and its influence on mechanical and corrosion behaviors in a high-Al/Zn containing duplex Mg-Li alloy after friction stir processing

Yixing Zhua,b,1, Mengran Zhoua,b,1,*, Yingxin Genga,b, Shun Zhangc, Tongzheng Xind, Gaoqiang Chena,b, Yifan Zhoua,b, Xiaoyu Zhoua,b,e, Ruizhi Wuc, Qingyu Shia,b   

  1. aState Key Laboratory of Clean and Efficient Turbomachinery Power Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China;
    bKey Laboratory for Advanced Materials Processing Technology, Ministry of Education, Beijing 100084, China;
    cKey Laboratory of Superlight Materials & Surface Technology (Ministry of Education), Harbin Engineering University, Harbin 150001, China;
    dKey Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China;
    eBeijing North Vehicle Group Corporation, Beijing 100072, China
  • Received:2023-08-27 Revised:2023-10-10 Accepted:2023-10-13 Published:2024-06-10 Online:2023-12-09
  • Contact: *E-mail address: zhoumr888@mail.tsinghua.edu.cn (M. Zhou)
  • About author:1These authors contributed equally to this work.

Abstract: Ultralight Mg-Li alloys offer promising applications across various fields. Mg-Li alloys enriched with Al and Zn hold theoretical potential for achieving excellent mechanical strength and corrosion resistance. However, the structural and performance characteristics of such Mg-Li alloys, particularly after thermomechanical processing, remain inadequately explored and understood. This study investigated the microstructural evolution of a Mg-9Li-5Al-4Zn alloy after friction stir processing and its consequent effects on the mechanical and corrosion performance. The grain size of the alloy was effectively refined and stabilized during friction stir processing at various heat inputs. The yield strength of the alloy increased by 86.4% after friction stir processing under the highest heat input condition, which was attributed to fine grain strengthening, solid solution strengthening and dispersion strengthening. Concurrently, the alloy experienced a slight decrease in elongation after the friction stir processing. The alloy subjected to friction stir processing with the highest heat input exhibited a minimal corrosion current density of 6.10 × 10-6 A/cm2, which was only 25% of the base metal. The enhanced anti-corrosion properties can be attributed to the dispersion and distribution of precipitated particles induced by friction stir processing, which hindered the micro-galvanic corrosion and promoted the generation of a compact surface film, leading to minimal and uniform corrosion. This investigation can be significant for understanding the metallurgical mechanisms and performance evolution of Mg-Li alloys during thermomechanical processes.

Key words: Mg-Li-Al-Zn alloy, Friction stir processing, Microstructure evolution, Thermal-mechanical stability, Corrosion behavior