Si、Mg含量对Al-Mg-Si合金显微组织及显微硬度的影响  

Effect of Si,Mg content on microstructure and microhardness of Al-Mg-Si alloy

作　　者：李佳双 屈敏[1] 崔岩[1] 刘峰斌[1] Li Jiashuang Qu Min Cui Yan Liu Fengbin(College of Mechanical and Materials Engineering, North China University of Technology, Beijing 100144, China)

机构地区：[1]北方工业大学机械与材料工程学院,北京100144

出　　处：《金属热处理》2016年第12期69-74,共6页Heat Treatment of Metals

基　　金：国家高技术研究发展计划(863计划)(2013AA031202);北京市属高等学校高层次人才引进与培养计划(CIT&TCD20130301);北京市优秀人才资助项目(2014000020124G010)

摘　　要：通过添加不同含量Si和Mg,研究Si、Mg对Al-Mg-Si合金显微组织与显微硬度的影响。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和显微硬度计分别对合金的微观形貌、相组成及显微硬度进行测试分析。结果表明:合金中主要有初生α-Al、骨骼状Mg_2Si相、板片状共晶Si,还会出现少量的Al_9Si、Al_8Si_6Mg_3Fe、Al_(0.3)Fe_3Si_(0.7)和Al_(0.5)Fe_3Si_(0.5)。随着Si含量的增加,Al-Mg-Si合金中α-Al枝晶变得细小,初生硅含量增加。随着Mg含量的增加,α-Al枝晶变粗、变大,从α-Al基体和初晶Si中的析出相逐渐明显,Mg_2Si强化相聚集长大,同时α-Al初生晶尺寸增大。随着Si含量的增加,Al-Mg-Si合金的显微硬度也随之提高。随着Mg含量的增加,合金显微硬度先增大后减小。Effect of Si, Mg content on microstructure and microhardness of Al-Mg-Si casting alloys by adding different content of Si, Mg was investigated. Microstructure, phase composition and microhardness of the alloy were tested and analyzed by scanning electron microscopy （SEM）, X-ray diffraction（XRD）and micro hardness tester. The results show that the microstructure mainly includes primary α-Al phase, skeletons Mg2 Si phase, plate-like eutectic Si, moreover, there exists a small amount of A19 Si, Al8Si6 Mg3 Fe, Alo. 3 Fe3 Sio. 7 and Alo. 5 Fe3 Sio. s. With the increase of Si content, the α-Al dendrite in the Al-Mg-Si alloy becomes small and the content of the primary Si increases. With the increase of Mg content, the a-A1 dendrite becomes thicker and biger, The precipitation phase of α-Al matrix and primary Si gradually became apparent, and the Mg2Si strengthening phase grew up, the size of α-Al primary crystal increased simultaneously. With the increase of Si content, the microhardness of Al-Mg-Si alloy is improved, with the increase of Mg content, the hardness of Al-Mg-Si alloy increases first and then decreases.

关 键 词：AL-MG-SI合金 SI含量 MN含量 组织 硬度 

分 类 号：TG146[一般工业技术—材料科学与工程]