Controlling the biodegradation rate of magnesium alloys through optimized machining process parameters

Magnesium alloys are emerging as potential candidates for temporary bone implants even if their practical applications are still limited because of their poor corrosion resistance inside the human body. The objective of the present work is to investigate the role of different machining parameters, namely the cooling strategy and the feed rate, on the degradation behaviour and wettability of the AZ31 magnesium alloy. Cryogenic machining was used to obtain the formation of a featureless layer near the machined surface, as well as the strategy of modifying the feed rate was used for controlling the surface wettability. In-vitro degradation tests together with potentyodinamic polarization curves showed an ennobled corrosion behavior for the cryogenic and feed rate optimized machined samples. These results clearly demonstrate that the careful choice of the process parameters promotes a synergistic effect that can be exploited in increasing the service-life of magnesium biodegradable implants.