Laser treated magnesium-based alloy: A potential candidate for biodegradable implants

The aim of this paper is to show that laser treated magnesium-based alloys can be a potential candidate for biodegradable implants. Magnesium alloys are biocompatible, lightweight and have good mechanical properties. The poor corrosion resistance of magnesium-based alloys can be advantageously used as biodegradable implants. However, the key issue is that, magnesium corrosion is too high in the physiological system which deteriorates the mechanical integrity of the alloy very rapidly. This study explores the possibility of enhancing the corrosion resistance of magnesium alloy (AZ31) through laser treatment, which has an advantage of unaltering the bulk chemical composition and thus the mechanical property is not compromised. Electrochemical polarisation experiments, showed increment in general corrosion resistance for laser treated alloy. High pitting corrosion resistance of laser treated alloy was observed in the salt spray tests. The stress corrosion cracking resistance was also significantly higher in the laser treated alloy as compared to the untreated alloy. The higher corrosion resistance in the laser treated alloy is attributed to the fine grain size, uniform distribution of the secondary phase particles along the grain boundary and aluminium enrichment on the surface. The study shows that suitable biodegradable magnesium-based orthopaedic implants can be achieved through laser treatment