Corrosion, stress corrosion cracking and corrosion fatigue behavior of magnesium alloy bioimplants

Abstract The use of magnesium and its alloys as temporary implants has gained interest in the last two decades due to their good mechanical properties and bio-degradability in the in-vivo conditions. However, the issues of higher corrosion rate and stress corrosion cracking persist, which are responsible for the implants’ early failure. This review paper focuses on the challenges involved in the use of magnesium-based implants and the advancements in mitigating the corrosion-related issues for in-vivo use of biodegradable magnesium alloy implants. Herein we review the degradation behavior of three groups of magnesium alloys, i.e., aluminum-containing Mg alloy, rare earth element (REE) containing Mg alloy, and aluminum-free Mg alloy in a variety of testing media. We also review various surface modification techniques such as mechanical methods, physical methods, and chemical methods adopted to address the shortcomings of the Mg alloys. Furthermore, recent developments in Mg based bioimplants such as Mg-based open porous scaffolds, nanostructured Mg alloys and Mg based bulk metallic glasses are reviewed. In the end, recent clinical trials of the Mg-based implant were reported in detail.