Stress-assisted degradation of magnesium alloys for biomedical applications: A comprehensive review

Recently, the topic of bioresorbable metals, with much focus on magnesium alloys for orthopedic implants, cardiovascular stents, and barrier membranes, has been an area of considerable investigation. During in vivo service, Mg alloy-based implants are inevitably subjected to complex biomechanical loading including tension, compression, fluid induced shear stresses. Given their inherent stress corrosion susceptibility, performance of Mg implants may deteriorate faster than expected under combined corrosion attack and mechanical stress. However, systematic understanding of stress-assisted corrosion mechanisms in biodegradable Mg alloys, particularly under physiologically relevant conditions, remains limited. This review comprehensively summarizes the qualitative and quantitative investigations on stress-assisted corrosion of Mg alloys both in vitro and in vivo . Key influencing factors, including alloy composition, corrosive media, and stress modes, are critically reviewed with emphasis on the corrosion performance, corrosion-induced mechanical degeneration of Mg alloys and the underlying mechanisms. Specifically, recent advances in materials design and structural optimization strategies aimed at mitigating stress-corrosion coupling are discussed. This review offers fundamental insights for the rational design of Mg-based implants with improved structural reliability and controlled degradation behavior, therefore supporting their clinical applications.