Effect of volume fraction of 18R-LPSO phase on corrosion resistance of Mg−Zn−Y alloys
Guoqiang Xi, Yu Mou, Yan Ma, Xuhan Zhao, Ju Xiong, Kai Ma, Jingfeng Wang
Abstract
This study aims to elucidate the effect of LPSO phases on the corrosion behavior of magnesium alloys through experimental design. The microstructure and corrosion behavior of four Mg−Zn−Y alloys designed according to the minimum structural unit for forming the 18R-LPSO phase, i.e. Zn/Y=3/4 (molar ratio), were studied in a comparative manner. The results showed that the alloys mainly contained α-Mg and 18R-LPSO phases, and the volume fraction of the 18R-LPSO phase increased with the increase of Zn and Y contents. The volume fraction of the 18R-LPSO phase in the four alloys was, in sequence, 16.55%, 34.45%, 54.24% and 70.36%, and the spatial distribution of the 18R-LPSO phase also changed from discrete blocks to continuous networks. When the volume fraction was about 50%, the corrosion resistance of the alloy was the best. When the volume fraction was greater than or less than 50%, the corrosion resistance of the alloy decreased.