微量钪对超高强Al-Zn-Cu-Mg-Zr合金组织与性能的影响  

Effect of Minor Scandium Addition on Microstructures and Tensile Properties of Super-High Strength Al-Zn-Cu-Mg-Zr Alloys

作　　者：邹亮[1] 潘清林[1] 何运斌[1] 王昌臻[1] 梁文杰[1] 李文斌[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《中国稀土学报》2007年第4期448-453,共6页Journal of the Chinese Society of Rare Earths

基　　金：国家863高技术新材料课题(2006AA03Z523)资助项目

摘　　要：采用铸锭冶金法制备了5种不同Sc含量的超高强Al-8.1Zn-2.3Cu-2.05Mg-0.12Zr合金,利用光学显微镜和透射电镜以及扫描电镜分别观察了合金的显微组织与断口形貌,测试分析了合金的拉伸力学性能。结果表明:采用Sc微合金化,凝固过程中形成的初生Al3(Sc,Zr)粒子可显著细化合金铸态晶粒组织,消除枝晶偏析,均匀化过程中形成的次生Al3(Sc,Zr)粒子可抑制合金的再结晶,并强烈钉扎位错及亚结构;微量Sc的添加使合金强度提高26～94MPa,同时保持较高的伸长率,合金拉伸断口表现为层状和韧窝混合型形貌特征,合金中适宜的Sc添加量为0.21%。Five kinds of Al-Zn-Cu-Mg-Zr based alloys with 0.1%, 0.2%, 0.3%, 0.5% Sc （mass fraction） addition and without Sc were prepared by ingot metallurgy. Using optical microscopy （O M）, transmission electronic microscopy （ TEM ） and scanning electronic microscopy（SEM）, the effect of microalloying element of Sc on the microstructure of super-high strength Al-Zn-Cu-Mg-Zr alloys related to mechanical properties was investigated. The results showed that the addition of minor Sc results in the formation of AI3 （Sc, Zr） particles. These particles were highly effec-tive in refining the microstructures, banishing the dendritic structures, retarding recrystallization, pinning dislocations and substructures. The tensile strength of Al-Zn-Cu-Mg-Zr alloys was through adding minor Sc, improved by 26- 94 MPa meanwhile the ductility of the studied alloys remained at a higher level. The studied alloys showed mixed fracture modes which were characterized by dimples and laminated pattern＇s coexisting after adding minor Sc. The optimal percentage of Sc addition is 0.21% in the studied alloys.

关 键 词：Al-Zn-Cu—Mg-Zr合金 AL3(Sc  Zr)相 微观组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]