Sc对亚共晶Al-11Mg2Si合金组织与力学性能的影响  

Effect of Sc on Microstructure and Mechanical Properties of Hypoeutectic Al-11Mg2Si Alloy

作　　者：王钰 李青春[1] 伍复发[1] 高浩东 武晓峰[1] WANG Yu;LI Qingchun;WU Fufa;GAO Haodong;WU Xiaofeng(School of Materials Science and Engineering,Liaoning University of Technology,Jinzhou 121001,China)

机构地区：[1]辽宁工业大学材料科学与工程学院

出　　处：《热加工工艺》2019年第20期42-46,52,共6页Hot Working Technology

基　　金：国家自然科学基金项目(51571106);辽宁省自然科学基金项目(2015020244;201602366)

摘　　要：通过XRD分析、金相显微镜(OM)和扫描电镜(SEM)观察及拉伸力学性能测试等手段,研究了添加稀土元素Sc对亚共晶Al-11Mg2Si合金显微组织及力学性能的影响。结果表明:在Al-11Mg2Si合金中添加适量的Sc对初生α-Al和共晶Mg2Si相同时起到良好的细化和变质作用。α-Al晶体由粗大的树枝晶转变为细小的球状晶,其平均尺寸由67.72μm减小至最小14.28μm;共晶Mg2Si由粗大的片层状转变为细小的纤维状和颗粒状,其平均尺寸由12.37μm减小至最小1.80μm。经0.25%Sc处理后,合金的抗拉强度、伸长率和硬度分别由未细化、变质的269 MPa、5.2%和35HRB提高到334 MPa、9.4%和53 HRB,分别提高了24.2%、80.8%和51.4%。含0.25%Sc合金断口中大量形成韧窝,其断裂模式从脆性转变为韧性。The effects of Sc addition on the microstructure and mechanical properties of hypoeutectic Al-11 Mg2Si alloy were studied by XRD analysis,OM and SEM observation and tensile test. The results show that the addition of proper amount of Sc has significant refine and modification effect on the eutectic Mg2Si and primary α-Al in the Al-11 Mg2Si alloy. The morphology of primary α-Al phase changes from coarse dendrite to fine spheroidal crystals, its average size is refined from67.72 μm minimum value of to 14.28 μm. Moreover, the morphology of the eutectic Mg2Si phase is altered from flake-like to very short fibrous or dot-like, its average size is refined from 12.37 μm to minimum value of 1.80 μm. The tensile strength,elongation and hardness of the alloy treated by 0.25%Sc increase by 24.2% 、80.8% and 51.4%, from 269 MPa, 5.2% and 35 HRB to 334 MPa, 9.4% and 53 HRB, respectively. The formation of a large number of dimples in the alloy with 0.25%Sc makes the fracture mode change from brittleness to toughness.

关 键 词：亚共晶Al-Mg2Si合金 SC 初生Α-AL 共晶Mg2Si 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]