微量锡对AA7085铝合金组织与性能的影响  

Influences of Trace Sn on Microstructure and Property of AA7085 Aluminum Alloy

作　　者：肖芳辉 刘华山[1] 杨冯[1] 董思思[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：《矿冶工程》2014年第6期119-122,127,共5页Mining and Metallurgical Engineering

基　　金：国家重点基础研究发展计划(2010CB731706)

摘　　要：利用金相显微镜、扫描电镜(SEM)、X射线衍射(XRD)、透射电镜(TEM)、维氏硬度计、断裂韧性性能测试等实验手段,研究了添加0.1%Sn对AA7085铝合金组织与性能的影响。结果表明:添加含量为0.1%的Sn能够细化AA7085合金的铸态组织,形成了Mg2Sn的第二相,且该相在后续的热处理过程中能够保留下来;添加Sn能够加快AA7085铝合金120℃下的时效初期的时效响应速度,延缓峰值时效出现的时间,同时使合金在过时效阶段保持较高的硬度和较低的硬度降低速率;另外,添加Sn的AA7085的抗拉强度和屈服强度分别为511 MPa和468 MPa,比未添加Sn的合金的抗拉强度和屈服强度(504 MPa和441 MPa)均有所提高,断裂韧性也从33.8 MPa·m1/2提高到35.5 MPa·m1/2,表现出良好的综合力学性能。Influences of 0.1% Sn addition on the microstructure and mechanical properties of AA7085 alloys were investigated through fracture toughness testing and Vickers hardness testing combined with metallurgical microscope, scanning electron microscope （SEM）, X-ray diffraction and transmission electron microscope （TEM）. The results show that the addition of 0.1% Sn can made the as-cast structure of AA7085 alloy finer, forming Mg2Sn second phase which will remain during the subsequent heat-treatment. Adding Sn can speed up the ageing response speed of AA7085 alloy at 120 ℃ in early aging, as well as delay the time to reach peak ageing, meanwhile, resulting in the alloy with a higher hardness and lower decreasing rate in hardness during the overaging stage. Furthermore, the tensile strength and yield strength of the AA7085-Sn alloy are 511 MPa and 468 MPa, respectively, higher than those of the alloy without Sn addition（504 MPa and 441 MPa）. The fracture toughness of the AA7085-Sn alloy also increases from 33.8 MPa · m1/2 to 35.5 MPa ·m1/2, exhibiting good comprehensive mechanical properties.

关 键 词：AA7085合金 锡 组织 时效硬化 断裂韧性 

分 类 号：TG146[一般工业技术—材料科学与工程]