Electrochemical and corrosion behaviors of the wrought Mg-Y-Zn based alloys with high Y/Zn mole ratios

The electrochemical behaviors and corrosion resistance of the wrought Mg-Y-Zn based alloys with high Y/Zn mole ratio have been investigated in details. The results show that the corrosion resistance of the investigated Mg-Y-Zn based alloys are dependent on the modified arrangement of LPSO phase by adjusting Y/Zn mole ratios. Increasing the Y/Zn mole ratio not only greatly decreases the size of LPSO phase plates, but also leads to the precipitation of Mg24Y5 phase. The corrosion rate of Mg-Y-Zn based alloys greatly increases from 7.4 mg.cm(-2).day(-1) to 11.3 mg.cm(-2).day(-1) with increasing the Y/Zn mole ratio up to 3. It should be attributed to the decreasing size of LPSO phase plates as cathodes, further increasing the hydrogen evolution kinetics. The related corrosion mechanism is discussed in details. (C) 2020 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.

Automated summary

The corrosion resistance of Mg-Y-Zn based alloys is dependent on the adjusted Y/Zn mole ratio affecting the arrangement of LPSO phase. Increasing the Y/Zn mole ratio decreases the size of LPSO phase plates and leads to the precipitation of Mg24Y5 phase, which in turn greatly increases the corrosion rate of the alloys. This is attributed to the decreasing size of LPSO phase plates acting as cathodes, further increasing hydrogen evolution kinetics.