【作者】 冯义成； 王琴； 姜文勇； 王丽萍； 郭二军；

【Author】 FENG Yi-cheng;WANG Qin;JIANG Wen-yong;WANG Li-ping;GUO Er-jun;School of Materials Science and Engineering,Harbin University of Science and Technology;

【机构】 哈尔滨理工大学材料科学与工程学院；

【摘要】 本文以Mg-6Al为基体,添加碱金属元素Ca和稀土元素Nd为合金化元素,通过重力金属型铸造方法制备Mg-6Al-Ca-Nd合金铸锭。采用光学显微镜(OM),扫描电子显微镜(SEM),X射线衍射仪(XRD)和布氏硬度计对Mg-6Al-Ca-Nd合金进行了组织观察及力学性能表征。研究结果表明:铸态Mg-6Al合金呈明显的树枝晶形貌,晶间由α-Mg、β-Mg17Al12相组成。随Ca和Nd含量的增加,合金的α-Mg晶粒得到显著细化,树枝晶组织消失,等轴晶形成。β-Mg17Al12相减少直至消失,而伴随有高熔点相Al2Ca、Al2Nd的析出。随着Ca和Nd含量的增加,合金的硬度提高。Mg-6Al-4Ca-4Nd硬度值能达到58.0,相对于Mg-6Al合金,硬度增幅高达22.9%。更多还原

【Abstract】 The Mg-6Al-x Ca-x Nd alloys,which were alloyed by Ca and Nd element on basis of Mg-6Al alloy,were fabricated by gravity permanent mould method.The microstructure and mechanical property were characterized by optical microscope(OM),scanning electron microscope(SEM),X-ray diffractometer(XRD) and Brinell hardness tester.Experimental results show that as-cast Mg-6Al alloy is with typical dendritic morphology,which is consist of α-Mg matrix and divorced eutectic β-Mg17Al12 phase along the grain boundaries.With increasing of Ca and Nd elements content,the α-Mg grains of Mg-6Al-Ca-Nd alloy were refined obviously,and the dendritic structure disappeared and equiaxed grains appeared.Meanwhile,β-Mg17Al12 phase decreased until disappeared and intermetallic Al-Ca phases and Al-Nd phases increased.Moreover,with increasing of Ca and Nd element content,the hardness of Mg-6Al-Ca-Nd alloy increased,the value of hardness of Mg-6Al-4Ca-4Nd alloy was 58.0,which was higher by 22.9% than that of Mg-6Al alloy.更多还原