采用金属型铸造法制备Mg-4Zn-1Y(wt%)合金,并在450℃下挤压成棒材。利用光学显微镜、扫描电镜、X射线衍射、浸泡试验及电化学试验对铸态和挤压态Mg-4Zn-1Y微观组织、相组成及其在3.5%NaCl溶液中的腐蚀行为进行研究。结果表明:铸态合金的平均晶粒尺寸为50~60μm,而挤压态合金的平均晶粒尺寸降低到4~5μm。热挤压可明显提高合金的耐腐蚀性,且挤压态合金纵截面耐腐蚀性要稍优于横截面。在3.5%NaCl溶液中,挤压态合金纵截面的腐蚀速率仅为铸态合金腐蚀速率的1/2。 A Mg-4Zn-1Y (wt%) alloy was prepared by metal casting and extruded at 450 ° C into a bar. The microstructure and phase composition of as-cast and as-extruded Mg-4Zn-1Y microstructures and their corrosion behavior in 3.5% NaCl solution were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction, immersion test and electrochemical test. The results show that the average grain size of as-cast alloy is 50 ~ 60μm, while the average grain size of extruded alloy is reduced to 4 ~ 5μm. Hot extrusion can significantly improve the corrosion resistance of the alloy, and extruded alloy longitudinal section corrosion resistance slightly better than the cross-section. In 3.5% NaCl solution, the corrosion rate of the longitudinal section of extruded alloy is only 1/2 of the corrosion rate of as-cast alloy.