中文摘要：

研究了大挤压比（81：1）条件下Mg-Zn-Y合金在3．5％（质量分数）NaCl水溶液中的腐蚀行为。通过失重法和电化学法测试了合金的腐蚀性能，并对合金的微观腐蚀过程进行了分析。结果表明：随着Zn、Y含量的增加，准晶相含量逐渐增加，合金的耐蚀性能逐渐降低。准晶相和α-Mg基体界面处的α-Mg基体一侧优先发生腐蚀，随后一方面向基体扩宽延伸而形成腐蚀坑；另一方面逐渐沿I-phase与α-Mg基体界面扩展，直至界面结合处形成裂纹环路而导致I-phase颗粒脱落，进而在合金表面形成点蚀坑。

英文摘要：

The corrosion behavior of extruded Mg-Zn-Y alloys at the large extrusion ratio of 81 ： 1 in 3. 5% NaCl solution were investigated. The corrosion properties of Mg-Zn-Y alloys were studied by immersion tests and electrochemical measurements. The results show that the volume fraction of I-phase increased with the increasing of Zn and Y contents, but the corrosion resistance of the alloys decreased. The α-Mg matrix surrounding the I-phase to be corroded preferentially, then on the one hand, corrosion extended toward the Mg matrix and formed corrosion pits. On the other hand, corrosion extended along the interface of I-phase and α-Mg matrix, until the formation of crack loop at the interface which caused the I-phase particles fall off from the substrate surface and formed corrosion pits.