Research Progress on Corrosion Fatigue Behavior of Novel Biomedical Degradable Magnesium-Based Alloys

Abstract:

Magnesium-based alloys were known as the new generation ‘revolutionary medical metal materials’, due to its better biological safety, excellent mechanical bearing effect and controllable degradation rate in vivo and in vitro. However, the corrosion resistance of magnesium alloy is very poor under the humid atmosphere. Particularly in a complicated human physiological environment, implant materials need to undergo the synergistic effects of dynamic alternating load and corrosive medium. Thus, it can cause the mechanical fixation and mechanical support roles of the Mg-based alloys decreased dramatically, resulting in the premature implantation failure. As a result, the coupling mechanism of applied load, frequency and corrosion factors affecting fatigue failure of medical magnesium alloys was investigated. In view of the quantitative relationships between corrosion fatigue life, fracture micro-zone characteristics and corrosion rate of biomedical Mg alloys in vivo and in vitro, the microscopic mechanism of corrosion fatigue failure under cyclic loading was described. Meantime, the initiation and propagation mechanism of fatigue micro-cracks were thoroughly analyzed; the improvement methods of corrosion fatigue properties of Mg alloys were comprehensively summarized; and the application prospect and development direction of biodegradable magnesium alloys for biomedical use were forecasted.

Key words:Biodegradable Mg alloys, corrosion fatigue, fatigue cracks, fatigue life，fracture mechanism