Ce对铸造Mg-5Al-2Si合金中Mg2Si相改性及力学性能的影响  

Effects of Ce on Mg2Si Phase Modification and Mechanical Properties of Mg-5Al-2Si Alloy

作　　者：朱文杰 李德江[1] 曾小勤[1] Seul Bi Lee Ik Min Park ZHU Wen-jie;LI De-jiang;ZENG Xiao-qin;Seul Bi Lee;Ik Min Park(School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;Department of Materials Science and Engineering, Pusan National University, Busan 46287, Korea)

机构地区：[1]上海交通大学材料科学与工程学院,上海200240 [2]釜山国立大学,韩国釜山46287

出　　处：《铸造》2019年第7期679-683,共5页Foundry

基　　金：国家重点研发计划项目(2016YFB0301002);韩国国家研究基金会(NRF)资助的全球前沿计划项目(2013M3A6B1078874)

摘　　要：利用X射线衍射、光学显微镜和扫描电镜等分析测试手段,研究了不同Ce添加量对重力铸造Mg-5Al-2Si合金显微组织和力学性能的影响规律。结果表明,添加Ce以后,合金中主要存在α-Mg相、汉字状Mg2Si相、多边形Mg2Si相、细小的Al11Ce3和CeSi2相;稀土Ce的加入改变了合金中Mg2Si相的尺寸、形貌与分布;随着Ce含量增加,汉字状Mg2Si相的平均长度大幅度减小,共晶Mg2Si相的形貌由粗大的汉字状转变为多边形状;当Ce添加量为0.4%时,试验合金的力学性能达到最佳,而增加至0.8%时,合金的力学性能反而下降。拉伸断口形貌也揭示了合金的力学性能情况。因此,适当的Ce添加量(0.4%)可以有效地改性Mg2Si相,从而提高合金的强度和伸长率。The effects of different contents of Ce on the microstructure and mechanical properties of gravity cast Mg- 5Al-2Si alloy were studied by means of X-ray diffraction, optical microscopy, scanning electron microscopy and mechanical property tests. The results reveal thatthe microstructure of Mg-5Al-2Si alloy without Ce addition consists of α-Mg phase, Chinese script Mg2Si phase, and polygonal Mg2Si phase;when Ce was added into the alloy, small amount of Al11Ce3 and CeSi2 phases appeared in the experimental alloys. The addition of Ce changes the size, morphology and distribution of Mg2Si phase in the alloy. With the increase of Ce content, the average length of Chinese script Mg2Si phase significantly decreases, and the morphology of eutectic Mg2Si phase transforms from large Chinese script type to polygonal type. When the amount of Ce addition is 0.4%, the size of Chinese script Mg2Si phase is reduced, and mechanical properties of the alloys are improved. However, the mechanical properties of the alloy decrease with Ce addition up to 0.8%. Tensile fractographs also reveal the effect of Ce on the mechanical properties of Mg-5Al-2Si alloy. Therefore, proper Ce addition (0.4%) can effectively modify Mg2Si phase, thereby increasing the strength and elongation ofMg-5Al-2Si alloy.

关 键 词：耐热镁合金 Mg-Al-Si系合金 汉字状Mg2Si相 显微组织 力学性能 

分 类 号：TG292[金属学及工艺—铸造]