Laser surface melting in liquid nitrogen of AZ31B magnesium alloy for microhardness and corrosion resistance improvement

摘要

Magnesium or its alloys have shown great potential as promising biocorrosive or biodegradable implantation materials and/or internal fixators, owing to their good biocompatibility and osteoinductive potential.However, poor anticorrosion property or rapid biodegradation in human body are serious impediments against wider application of Mg alloys.In the present work, a pulsed Nd : YAG laser was used to melt and rapidly solidify the surface of the magnesium alloy in liquid nitrogen with the objective of changing microstructure and improving the surface properties.The experimental results were compared with those of Ar gas protection at room temperature.The results indicate that laser-melted layer in liquid nitrogen is finer than in Ar gas protection and contains a lot of worm-like nanocrystals and local amorphous structures.Compared with the latter, the laser surface melting treatment in liquid nitrogen increased the microhardness of the AZ31B Mg-alloy and improved its corrosion resistance.