Regulating corrosion resistance of Mg alloys via promoting precipitation with trace Zr alloying.

Poor corrosion property has been a bottleneck problem during the application of Mg alloys. This work proposes a new way to improve the corrosion resistance of MgNd alloy by micro-alloying Zr, which promotes the precipitation process to rapidly form a protective corrosion layer. The corrosion rate decreases by three orders of magnitude from 32.69 mL/cm2/day to 0.072 mL/cm2/day. The results show Zr tends to form nano-scale oxide clusters on Mg surface, acting as pre-precipitation sites to accelerate the precipitation and facilitate the formation of dense and compact corrosion layer. [Display omitted] • Via micro-alloying Zr, the corrosion rate of Mg-Nd alloy decreases by three orders of magnitude to 0.072 mL/cm2/d. • The formation process of the corrosion layer was monitored and clarified by in-situ AFM and EN technique. • The oxide of Zr can act as pre-precipitate sits to accelerate the precipitation rate, leading to a dense and compact corrosion layer. [ABSTRACT FROM AUTHOR]