镁含量对高锌Al-9Zn-xMg-1Cu合金时效沉淀相及其强化作用的影响  

Effects of Mg content on precipitation and strengthening of high zinc Al-9Zn-xMg-1Cu alloy after aging

作　　者：刘安民 杨梦楚 张梦晗 刘胜胆[1,2,3] 唐建国[1,2,3] LIU An-min;YANG Meng-chu;ZHANG Meng-han;LIU Sheng-dan;TANG Jian-guo(School of Materials Science and Engineering,Central South University,Changsha 410083,China;National Key Laboratory of Science and Technology on High-strength Structural Materials,Central South University,Changsha 410083,China;Key Laboratory of Non-Ferrous Metal Materials Science and Engineering,Ministry of Education,Central South University,Changsha 410083,China)

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学轻质高强结构材料重点实验室,长沙410083 [3]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《中国有色金属学报》2023年第10期3117-3127,共11页The Chinese Journal of Nonferrous Metals

基　　金：国家重点研发计划资助项目(2016YFB0300901);国家自然科学基金资助项目(U21A20130)。

摘　　要：采用硬度测试和室温拉伸测试,结合透射电镜、高分辨透射电镜及几何相位分析技术,定量研究了Mg含量(1%~3%,质量分数)对高锌Al-9Zn-xMg-1Cu合金在120℃人工时效时沉淀相的影响,并探讨了强化作用。结果表明:当Mg含量从1%增至2%时,合金的屈服强度大幅增加,增加率约为37.7%;当Mg含量继续增至3%时,合金的屈服强度小幅增加,增加率仅为9.1%。Al-9Zn-1Mg-1Cu合金的强化相为η’相,Al-9Zn-2Mg-1Cu和Al-9Zn-3Mg-1Cu合金的强化相都为η’相和T’相。T’相引起的应变大于η’相,其强化效果更好;Mg含量变化对两种强化相引起的最大应变值影响不大。随着Mg含量增加,η’相的体积分数、数量密度及其比例减小,T’相的变化则相反,沉淀相的总数量密度和体积分数增大。基于η’相和T’相的尺寸、体积分数和数量密度,计算和分析了它们对沉淀强化的贡献,计算结果与实验结果基本一致。The effects of Mg content(1%-3%)on the precipitates and their strengthening effect of high zinc Al-9Zn-xMg-1Cu alloys treated by artificial aging at 120℃were investigated by hardness and room temperature tensile tests,combined with transmission electron microscopy,high resolution transmission electron microscopy and geometric phase analysis technique.The results show that the yield strength of the alloy increases significantly when the Mg content increases from 1%to 2%,with an increased rate of about 37.7%,and then increases slightly when the Mg content continuesly increase to 3%,with an increased rate of about 9.1%.The strengthening precipitates areη′phase in Al-9Zn-1Mg-1Cu alloy,andη′phase and T′phase in both Al-9Zn-2Mg-1Cu alloy and Al-9Zn-3Mg-1Cu alloy.The strain caused by T′phase is larger than that byη′phase,and therefore its strengthening effect is better;the change of Mg content has little effect on the maximum strain value caused by the above two strengthening phases.With the increase of Mg content,the volume fraction,number density and proportion ofη′phase decrease,while the change of T′phase shows an opposite trend;as a result,the total number density and volume fraction of precipitates increase.Based on the size,volume fraction and number density ofη′phase and T′phase,their contributions to precipitation strengthening are calculated and discussed,and the calculated results are basically consistent with the experimental results.

关 键 词：AL-ZN-MG-CU合金 Mg含量 时效硬化 屈服强度 沉淀强化相 

分 类 号：TG146.2[一般工业技术—材料科学与工程]