Schematic diagram illustrating the corrosion reaction in Mg–Li–Al–Ca alloy with and without β-Li phase

Abstract

The effect of Li on the microstructure and corrosion behavior of extruded Mg-xLi-3Al-0.4Ca (x = 4,5,6,7) alloys were investigated by hydrogen evolution, potentiodynamic polarization measurement and electrochemical impedance spectroscopy measurement. The single-phase 4Li alloy with the largest α-Mg grain size and the strongest basal texture intensity exhibits the best corrosion resistance in 3.5 wt% NaCl solution. The duplex 6Li and 7Li alloys contain a protective LiOH film in the corrosion products, giving them better corrosion resistance than 5Li alloy. This study provides a new insight for the design and preparation of Mg–Li alloys with high corrosion resistance.