Effect of Sr on the microstructure and corrosion properties of the as-cast Mg-Zn-Zr alloy

The effect of Sr on the microstructure of Mg-Zn-Zr alloys was investigated by means of scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. An immersion experiment and electrochemical experiment were designed to study the effect of Sr on the corrosion performance of the alloys. The results show that the addition of Sr promotes the formation of Mg17Sr2 phase in the alloy, and this stripe phase appears at the alloy grain boundaries. With the increase in Sr content, a network structure is formed at the grain boundary, creating a corrosion barrier to prevent further corrosion of the alloy. The study found that Mg-4Zn-0.4Zr-1.0Sr alloy has the best corrosion performance.