Sc和Si相互作用对铸造Al-Si-Sc合金组织和性能的影响  

Effection of the Interaction Between Si and Sc on the Microstructure and Properties of As Casted Al-Si-Sc Alloys

作　　者：周荣虎[1] 周鹏飞[1] ZHOU Rong-hu;ZHOU Peng-fei(School of Automotive and Transportation,Yancheng Polytechnic College,Yancheng 224005,Jiangsu,China)

机构地区：[1]盐城工业职业技术学院汽车与交通学院,江苏盐城224005

出　　处：《铸造》2024年第5期612-620,共9页Foundry

基　　金：2022年度国家外国专家项目(G2022014146L);2022年度江苏省高校基础科学自然科学面上项目(22KJD430011);2022年江苏省产学研合作项目(BY20221011,2023hx-63);2023年校级高级人才科研项目(ygy6070014007);2023年校级博士基金项目(ygy2201)。

摘　　要：通常在铸造Al-Si合金加入Sc来改善合金的性能,但是Si和Sc的相互作用对合金组织和性能影响仍需要进一步深入研究。本文研究了不同含量的Si和Sc对合金组织和性能的影响,结果表明,Sc通过原位形成初生Al_(3)Sc作为α-Al异质形核质点从而细化α-Al晶粒;在凝固过程中,共晶反应生成了网格状AlSi_(2)Sc_(2)相,包晶反应形成了块状AlSi_(2)Sc_(2)相;两种AlSi_(2)Sc_(2)相都会消耗合金中Sc原子,从而降低了Al_(3)Sc的细化效果;Sc还变质共晶Si为更有序的纤维/片状结构,适当的Si与Sc的比可以避免AlSi_(2)Sc_(2)的形成;Al-6Si中Sc含量从0.3%增加至1%时,抗拉强度和屈服强度均上升,但由于AlSi_(2)Sc_(2)相的存在,其伸长率下降;当Sc含量为1%、Si含量从6%降至3%时,抗拉强度、屈服强度和伸长率分别上升2%、12%和21%,主要是凝固过程中析出了Al_(3)Sc而非AlSi_(2)Sc_(2)相。最后,还讨论了Si-Sc交互作用对组织演变的机制。Scandium(Sc)and silicon(Si)are effective for modifying Al based alloys,while their combined effect may be limited by some Si-Sc interaction,which still need to be further studied.In this paper,Al alloys with varying Si and Sc additions were prepared for microstructure characterization and tensile testing.The results showed that Sc refines theα-Al grain via a heterogeneous nucleation induced by in-situ formed primary Al_(3)Sc.A network AlSi_(2)Sc_(2) phase was formed via a eutectic reaction and a bulk AlSi_(2)Sc_(2) was generated from a peritectic reaction.Both AlSi_(2)Sc_(2) competitively consumed the Sc solute in the same alloy,weakening the refining effectiveness of Al_(3)Sc.The Sc also refined the eutectic Si to more ordered fiber/plate-like structure,and a proper ratio of Si to Sc could avoid the AlSi_(2)Sc_(2) formation.When increasing Sc from 0.3 to 1.0 wt%in Al alloys containing 6%Si,the ultimate tensile strength(UTS)and yield strength(YS)increased,but the EL decreased due to the presence of AlSi_(2)Sc_(2) phase.When the Sc content was 1%and the Si content reduced from 6%to 3%,the tensile strength,yield strength and elongation increase by 2%,12%and 21%,with Al_(3)Sc in a dominant role in solidification reactions without AlSi_(2)Sc_(2) formation.The mechanisms of microstructure modification with Si-Sc interaction were also discussed.

关 键 词：Al-Si-Sc合金 组织 异质形核 变质 

分 类 号：TG146.21[一般工业技术—材料科学与工程]