J. Mater. Sci. Technol. ›› 2024, Vol. 198: 243-258.DOI: 10.1016/j.jmst.2024.01.075

• Research article • Previous Articles    

A spatiotemporal “bulk erosion” mode in selective laser melted magnesium alloys and the resulting adverse cell & tissue responses

Dong Biana,1, Zhipei Tonga,1, Gencheng Gonga,b,1, He Huangc, Guixing Caid, Xingchen Yane, Hui Yuf,*, Cheng Change,*, Yufeng Zhenga,g,*   

  1. aMedical Research Institute, Department of Orthopedics, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China;
    bSchool of Medicine, South China University of Technology, Guangzhou 510006, China;
    cSchool of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450003, China;
    dGuangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China;
    eGuangdong Provincial Key Laboratory of Modern Surface Engineering Technology, National Engineering Laboratory of Modern Materials Surface Engineering Technology, Institute of New Materials, Guangdong Academy of Sciences, Guangzhou 510651, China;
    fDepartment of Orthopaedic Surgery, Guangzhou Key Laboratory of Spine Disease Prevention and Treatment, Guangdong Provincial Key Laboratory of Major Obstetric Diseases, Guangdong Provincial Clinical Research Center for Obstetrics and Gynecology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510515, China;
    gSchool of Materials Science and Engineering, Peking University, Beijing 100871, China
  • Received:2023-11-20 Revised:2024-01-08 Accepted:2024-01-13 Published:2024-11-01 Online:2024-03-15
  • Contact: *E-mail addresses: yanxingchen@gdinm.com (X. Yan), yuhuijm@outlook.com (H. Yu), cheng.chang1993@hotmail.com (C. Chang), yfzheng@pku.edu.cn (Y. Zheng)
  • About author:1 Those authors contributed equally to this work.

Abstract: Selective laser melting (SLM) has attracted great attention in the fabrication of magnesium-based biodegradable implants. However, current SLMed magnesium alloys are generally suffered from rapid corrosion, which is deadly detrimental to their use. Herein, we thoroughly revealed why they are so vulnerable to corrosion through a typical SLMed AZ91D material model. An abnormally spatiotemporal “bulk erosion” mechanism was found, not the well-known “surface corrosion” mode of traditionally plastic-deformed alloys. The unique microstructure derived from SLM possesses high chemical reactivity, which is favorable for interactional attacks of fast fluid penetration, severe local corrosion and intensive micro-galvanic corrosion. Thus, it brings two orders of magnitude in corrosion rates compared with its plastic-deformed counterparts. In vitro, such fast-corrosion induced apparent cytotoxicity, cell damage, and further apoptosis to rat and mouse derived mesenchymal stem cells. In vivo, the material disintegrates into small pieces in a short period, and results in unexpected bone destruction and long-lasting foreign body reactions in Sprague Dawley rats. Close attention should be paid to this issue before SLMed Mg-based implants being applied in patients.

Key words: Selective laser melting, Biodegradable magnesium, Bulk erosion, Microstructural defect, Adverse biological response