Mechanical behaviour of biodegradable AZ31 magnesium alloy after long term in vitro degradation

Adekanmbi, I., Mosher, C. Z., Lu, H. H., Riehle, M. , Kubba, H. and Tanner, K. E. (2017) Mechanical behaviour of biodegradable AZ31 magnesium alloy after long term in vitro degradation. Materials Science and Engineering C: Biomimetic and Supramolecular Systems, 77, pp. 1135-1144. (doi: 10.1016/j.msec.2017.03.216)

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Abstract

Biodegradable magnesium alloys including AZ31 are exciting candidates for temporary implants as they eliminate the requirement for surgical removal, yet have higher mechanical properties than degradable polymers. However, the very long term mechanical properties and degradation of these alloys have not been fully characterized. The tensile, bending and corrosion behaviour of biodegradable AZ31 Mg alloy specimens have been investigated for up to 9 months in vitro in phosphate buffered saline (PBS). Small AZ31 Mg specimens showed a significant drop in bend yield strength and modulus after 3 months in vitro degradation and an average mass loss of 6.1%. Larger dumbbell specimens showed significant drops in tensile strength from 251.96 ± 3.53 MPa to 73.5 ± 20.2 MPa and to 6.43 ± 0.9 MPa and in modulus from 47.8 ± 5.6GPa to 25.01 ± 3.4GPa and 2.36 ± 0.89GPa after 3 and 9 months respectively. These reductions were accompanied by an average mass loss of 18.3% in 9 months. Degradation rate for the small and large specimens followed similar profiles with immersion time, with peak degradation rates of 0.1747 g m− 2 h−1 and 0.0881 g m− 2 h−1, and average rates of 0.1038 g m− 2 h−1 and 0.0397 g m− 2 h−1 respectively. SEM fractography and polished specimen cross-sections revealed corrosion pits, cracks and corrosion induced defects. These data indicate the potential of AZ31 Mg for use in implants that require medium term degradation with load bearing mechanical properties.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Adekanmbi, Dr Isaiah and Riehle, Dr Mathis and Kubba, Mr Haytham and Tanner, Professor Kathleen
Authors: Adekanmbi, I., Mosher, C. Z., Lu, H. H., Riehle, M., Kubba, H., and Tanner, K. E.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
College of Science and Engineering > School of Engineering > Biomedical Engineering
Journal Name:Materials Science and Engineering C: Biomimetic and Supramolecular Systems
Publisher:Elsevier
ISSN:0928-4931
ISSN (Online):0928-4931
Published Online:25 March 2017
Copyright Holders:Copyright © 2017 Elsevier
First Published:First published in Materials Science and Engineering C: Biomimetic and Supramolecular Systems 77: 1135-1144
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
632171Breathe deep - Opening up the windpipe in childrenK TannerAction Medical Research (ACTMEDRE)GN2223ENG - BIOMEDICAL ENGINEERING