含有长周期堆垛有序结构的Mg-Zn-Y镁合金显微组织与腐蚀性能.docVIP

 含有长周期堆垛有序结构的 Mg-Zn-Y 镁合 金显微组织与腐蚀性能# 张金山，徐继东* 5 10 （太原理工大学材料学院，太原 030024） 摘要：利用常规铸造的方法制备了含有长周期堆垛有序结构的 Mg-Zn-Y 镁合金。用 OM,SEM,TEM 和 XRD 分析了合金显微组织及其组织演变过程。综合利用集气法、失重法和电 化学方法测试了合金的腐蚀性能和机理。结果表明，随着 Zn 和 Y 加入量的提高，合金中 Mg12YZn 相逐步增多，由不连续变为连续。腐蚀产物出现在 Mg 相和 X 相交界处，说明 Mg12YZn 相在合金中对镁基体有电偶加速效应。合金中的 Mg12YZn 相的形态和体积分数对腐蚀速率有 很大的影响, 在 Mg97Zn1Y 2 合金中,由于 Mg12YZn 相连续分布，合金的腐蚀速率最小。 关键词：镁合金；长周期结构；显微组织；Mg12YZn 相（X 相）；腐蚀性能 中图分类号：GT292 15 Microstructure and Corrosion Performance of Mg–Zn–Y Alloy with Long-period Stacking Ordered Structures ZHANG Jinshan, XU Jidong (College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 20 25 30 030024) Abstract: Mg-Zn-Y alloys with long-period stacking ordered structures were prepared by an ingot casting method. The microstructure evolution of Mg-Zn-Y alloys was analyzed by OM, SEM, TEM and XRD. The corrosion performance of Mg-Zn-Y alloys was studied by combining collecting gas test, immersion test and electrochemical measurements in order to determine the corrosion rate and mechanism of the alloys. The results showed that the volume fraction of Mg12YZn phase increased and the shape of the Mg12YZn phase changed from dis-continuous to continuous along with the increasing of Zn and Y. Corrosion products appeared at the junction of Mg phase and Mg12YZn phase, indicating that the X phases has galvanic accelerate effects to Mg matrix. The corrosion rate of the alloys was greatly depended on the distribution and volume fraction of the Mg12YZn phase. Mg97Zn1Y2 alloy shows the lowest corrosion rate due to the continuous distribution of X phase. Key words: Maguesium Alloy; Long-period Stacking Ordered（LPSO）Structure; Microstructure; Mg12YZn phase（X phase）; Corrosion Behavior 0 引言 35  [1,2] 镁合金由于具有低密度和高的比强度被认为是汽车和航天领域最有潜力的结构材料 。为了获得更优异的性能和更广阔的应用空间，在镁合金中开发更有效的增强相成为研 究的热点[3, 4]。近十年来，在 Mg-Zn-Er 三元合金中开发了一些含有长周期堆垛有序结构的新 型镁合金，这种合金具有优异的机械性能和独特的微观结构[5, 6]。据报道, 采用 RS/PM（快 速冷却/粉末冶金）方法制备的 Mg97Zn1Y2 合金在室温下具有极高的屈服强度和伸长率，其 40 数值分别为 61