摘要
采用稀土元素Sc对压铸Al-9.5Si-1.3Mg铝合金进行微合金化,借助金相显微镜、场发射扫描电子显微镜、维氏硬度计、万能试验机研究稀土元素Sc对Al-9.5Si-1.3Mg合金微观组织及力学性能的影响。结果表明:Sc元素可有效细化合金枝晶,减小二次枝晶臂间距,当Sc添加量为0.01%时,合金的二次枝晶臂间距平均为11.72μm,与未添加Sc合金相比,减少了60.19%;Sc能够改变共晶Si的形貌,能通过吸附在共晶Si表面,改变共晶Si的生长模式,使共晶Si从粗大片状向纤维状或颗粒状转变;Sc能够细化富铁相,含Sc合金中π-Al_(8)FeMg_(3)Si_(6)相长宽比减小,圆整度更高;当Sc添加量为0.02%时,合金的抗拉强度、延伸率分别为354.72 MPa、5.75%,此时质量指数Q最高,为468.67 MPa。
Rare earth element Sc was used to microalloy die-cast Al-9.5Si-1.3Mg aluminum alloy.The effect of rare earth element Sc on the micro-structure and mechanical properties of Al-9.5Si-1.3Mg alloy was studied by metallographic microscope,field-emission scanning electron microscope,Vickers hardness tester and universal testing machine.The results show that Sc can effectively refine the alloy dendrite and reduce the secondary dendrite arm spacing.When the mass fraction of Sc added is 0.01%,the average secondary dendrite arm spacing of the alloy is 11.72μm,which is reduced by 60.19% compared with the alloys without Sc;Sc can change the morphology of the eutectic Si,and change the growth mode of the eutectic Si by adsorbing on the surface of the eutectic Si,so as to make the eutectic Si change from coarse flake to fibrous or granular;Sc can refine the iron rich phase,the aspect ratio ofπ-Al_(8)FeMg_(3)Si_(6) phase in alloys containing Sc is reduced,and the roundness is higher;when the added mass fraction of Sc is 0.02%,the tensile strength and elongation of the alloy are 360.86 MPa and 6.16%respectively,and the quality index Q is the highest at 479.30 MPa.
作者
董亚轲
张煜琰
罗子相
梁霄鹏
谭孝芬
李慧中
DONG Yake;ZHANG Yuyan;LUO Zixiang;LIANG Xiaopeng;TAN Xiaofen;LI Huizhong(School ofMaterials Science and Engineering,Central South University,Changsha 410083,China;Shenzhen XinShen New Material Technology Co.,Ltd.,Shenzhen 518100,China;Key Laboratory ofNonferrous Metal Materials Science and Engineering,Ministry ofEducation,Central South University,Changsha 410083,China)
出处
《湖南有色金属》
2025年第4期72-78,共7页
Hunan Nonferrous Metals
