Sc对Al-Si-Mg-Cu-Ti合金铸态组织和力学性能的影响  

Effect of Sc on as-cast microstructures and mechanical properties of Al-Si-Mg-Cu-Ti alloys

作　　者：张雅 杜晓东[1] 李玉坤[1] 胡孝德 郝放 吴玉程[1] Zhang Ya1, Du Xiaodong1, Li Yukun1, Hu Xiaode2, Hao Fang2, Wu Yucheng1(1. Department of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China ; 2. Anhui Faster Auto Parts Co.,Ltd, Huaining 246121, Chin)

机构地区：[1]合肥工业大学材料科学与工程学院,安徽合肥230009 [2]安徽福斯特汽车部件有限公司,安徽怀宁246121

出　　处：《轻金属》2018年第3期49-52,共4页Light Metals

基　　金：安徽省科技攻关计划项目(1704a0902060);安徽省科技攻关计划重大项目(1301021006)

摘　　要：借助金相显微镜、扫描电镜、透射电镜、布氏硬度计和万能试验机,试验研究了Sc对Al-3.0Si-0.45Mg-0.45Cu-0.15Ti合金铸态组织和力学性能的影响。结果表明,在试验合金中添加稀土元素Sc,使合金在凝固过程中析出Al3(Sc,Ti)初生相,初生相与α(Al)基体共格,符合点阵匹配原理,成为有效的非均质晶核,可显著细化合金的铸态组织。随着Sc含量(w(Sc)0~0.56%)的增加,合金的铸态组织由粗大的树枝晶变为细小的等轴晶,合金的硬度、抗拉强度和伸长率也随着Sc含量的增加而升高。时效过程中析出的Al3(Sc,Ti)沉淀相密度高,细小弥散,具有钉扎位错,稳定亚结构,阻碍亚晶长大及晶界迁移的作用。The influences of Sc addition on the casting structures and mechanical properties of Al -3.0Si -0.45 Mg -0.45 C u -0.15Ti alloys were inves- tigated by metallographic microscope, scanning electron microscopy with energy dispersive X - ray （ SEM - EDX） , transmission electron microscopy （TEM）, Brinell tester and universal testing machine. The result shows that the primary Al3 （Sc, Ti） particles precipitated from the melt during solidifica- tion produce a substantial refinement of grain size of as - cast microstructures of the alloys, which have the same crystal structure of α （ A1 ）, and comply with the lattice matching principle. With increase content of Sc （0 -0.56% ）, the growth morphology of as - cast microstructures change from denfritic to fine equiaxed grain. The hardness, tensile strength and elongation are also enhanced with the increase content of Sc. The dispersed secondary Al3 （ Sc, Ti） precipitated during aging treatment can strongly pin dislocations, stabilize substructures and inhibit subgrain growth and the movement of boundaries.

关 键 词：Al-Si-Mg-Cu-Ti合金 Al3(Sc Ti) 晶粒细化 沉淀强化 

分 类 号：TG146.21[一般工业技术—材料科学与工程]