微量AlFeCuTi多元合金对Al-7Si合金微观组织及其力学性能的影响  

Microstructure and Mechanical Properties of Al-7Si Alloy with Trace AlFeCuTi Alloy Addition

作　　者：王凯龙 王平波 张岩 乔朝勃 李庆林[1] Wang Kailong;Wang Pingo;Zhang Yan;Qiao Zhaobo;Li Qinglin(School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Wuxi Huarun CSMC Technologies Corporation,Wuxi 214028,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]兰州理工大学材料科学与工程学院,甘肃兰州730050 [2]无锡华润上华科技有限公司,江苏无锡214028 [3]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属》2024年第7期922-932,共11页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51561021);甘肃省重点研发计划项目(21YF5GA075);甘肃省科技专员专项(23CXGA0026);甘肃省优秀研究生“创新之星”项目(2023CXZX-392)资助。

摘　　要：采用真空电弧熔炼炉制备了AlFeCuTi多元合金(原子比为1∶1∶1∶1),研究AlFeCuTi中间合金添加含量(0.3%和0.5%,质量分数)对Al-7Si合金显微组织和力学性能的影响。结果表明:当Al-7Si合金中添加0.3%的AlFeCuTi多元合金时,初生α-Al从粗大的树枝晶被细化为细小的等轴枝晶,其平均晶粒尺寸从218μm减小到53.6μm;二次枝晶臂间距(SDAS)从25μm减小到8.2μm;共晶Si组织从粗大的针片状被变质为细小的粒状和短片状,其平均长度从34.8μm减小到8.9μm,平均宽度从4μm减小到0.85μm。然而,进一步增加AlFeCuTi中间合金的添加量到0.5%时,α-Al和共晶Si组织没有进一步被细化,反而出现了粗化现象,但是比未变质组织要细小。拉伸测试结果表明:当Al-7Si合金中添加0.3%的AlFeCuTi中间合金时,抗拉强度(σ_b)和延伸率(δ)由未变质前的162 MPa和3%分别提高到190 MPa和6.5%。然而,当AlFeCuTi中间合金的添加含量增加到0.5%时,由于过变质现象的产生,导致合金力学性能下降。The hypoeutectic Al-Si alloys have many advantages,such as low density,high strength-to-weight ratio,good corrosion and wear resistance,low thermal expansion coefficient and good castability.However,the coarse need-like eutectic Si phases seriously split continuity ofα-Al matrix.Moreover,the sharp edges and corners of Si phases easily give rise to the stress concentration leading to the decrease of mechanical properties of Al-Si alloys,especially ductility.In addition,the forming coarseα-Al dendrites in the solidification can result in many casting defects,such as pores,snowflake spot,shrinkage porosity and serious composition segregation,which obviously decrease the strength and elongation of Al-Si casting alloys.Therefore,it is necessary to refine the primaryα-Al,and change the morphology and distribution of eutectic Si structure through modification treatment to improve the mechanical properties of hypoeutectic Al-7Si alloy.Compared with these methods of refining and modifying the primaryα-Al and eutectic Si structure including rapid solidification,heat treatment,mechanical agitation,high energy ultrasonic treatment,and adding nucleating agent,chemical modification through adding modifier among these methods has been extensively applied due to their good refining efficiency and low cost.Fe element adding to hypereutectic Al-Si alloys can modify the primary Si from coarse five-folded shape to small blocky shape,and the eutectic Si from coarse acicular to short rods shape.Ti addition can refine the dendritic crystals into equiaxed grains in Al-Si alloys.In addition,Cu addition to Al-Si alloys can precipitate Al,Cu phases,and some Cu atoms solid solution to Al play an important role in strengthening.Hence,it is very necessary to investigate the effect of complex adding Fe,Cu and Ti elements on microstructure and mechanical properties of Al-7Si alloy.The influences of adding AIFeCuTi alloy(0.3%and 0.5%,weight percent)was prepared by vacuum arc melting to systematically investigate the effect of trace Fe,Cu and

关 键 词：Al-7Si合金 AlFeCuTi多元合金 初生Α-AL 共晶Si 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]