Biodegradation mechanisms of selective laser-melted Mg–xAl–Zn alloy: grain size and intermetallic phase

ABSTRACT

Grain size and intermetallic phase were two key factors affecting the biodegradation behaviour of Mg alloys. In the paper, different grain size and intermetallic phase volume fraction were obtained by introducing Al into Mg–Zn alloy via selective laser melting. Results showed that the grain size refined while the intermetallic phase volume fraction increased with Al increasing. As Al was less than 3 wt.%, the grain refinement was the major factor affecting the degradation behaviour. The finer grain would create many grain boundaries, making the alloy passivate readily and resulted in a reduced degradation rate. However, with Al further increasing, the intermetallic phase became the main factor influencing the degradation behaviour though grain size was further refined. The large intermetallic phase volume fraction caused severe galvanic corrosion, accelerating the degradation. This work may provide guidance for balancing grain size and intermetallic phase on degradation behaviour of Mg alloys.

KEYWORDS:

• Degradation behaviour
• grain size
• intermetallic phase

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Prof. Shuai is a professor of Central South University. He works as a chief editor or editorial board member of many international journals, such as Current Biomedical Engineering, BioMed Research International, etc. He also works as invited reviewer for more than 30 international journals. He has published more than 180 papers and obtained 44 patent declaration and authorisation.

Mr. He is a postgraduate of Central South University. He has published 1 paper which is indexed by SCI.

Prof. Feng is a professor of Central South University. He works as chief editor or editorial board member of many international journals, such as Journal of Biomedical Engineering and Informatics, Nanoscience, and Nanometrology. He also works as invited reviewer for more than 20 international journals. He has published more than 60 SCI indexed papers and obtained 15 patent declaration and authorisation.

Dr. Guo is a doctor of Central South University. He has published 2 papers which are indexed by SCI.

Prof. Gao is a professor of Central South University. He works as a chief editor or editoral board member of many international journals, such as Journal of Engineering Mechanics and Machinery, and Journal of Osteoporosis and Physical Activity. He also works as invited reviewer for more than 20 international journals. He has published more than 60 SCI indexed papers and obtained 5 patent declaration and authorisation.

Prof. Wu is Professor of Xiangtan University. She has published more than 20 papers and obtained 6 patent declaration and authorisation.

Dr. Yang is a doctor of Central South University. He has published more than 10 papers and obtained 5 patent declaration and authorisation.

Dr. Bin is a Chief Technician of Department of Oncology, Third Xiangya Hospital of Central South University. She is also a doctor of Central South University. She has published 7 papers.

Additional information

Funding

This work was supported by The Project of Innovation-driven Plan of Central South University [grant number 2016CX023]; The Open-End Fund for the Valuable and Precision Instruments of Central South University; National Postdoctoral Program for Innovative Talents [grant number BX201700291]; The Natural Science Foundation of China [grant numbers 51575537, 81572577, 51705540]; The fund of the State Key Laboratory of Solidification Processing in NWPU [grant number SKLSP201605]; The Project of State Key Laboratory of High Performance Complex Manufacturing, Central South University and Hunan Provincial Natural Science Foundation of China: [grant number 2016JJ1027].