Al-Zn-Mg-Cu-Sc-Zr合金均匀化过程中的析出特性  

Precipitation behavior of Al-Zn-Mg-Cu-Sc-Zr alloy during homogenization process

作　　者：李亨[1,2] 唐锴 王汉 王可胜 李玉坤 吴玉程[1,3] LI Heng;TANG Kai;WANG Han;WANG Ke-sheng;LI Yu-kun;WU Yu-cheng(Anhui Province Key Laboratory of Aerospace Structural Parts Forming Technology and Equipment,Hefei University of Technology,Hefei 230009,China;Chinaland Solar Energy Co.,Ltd.,Hefei 231600,China;National-Local Joint Engineering Research Center of Nonferrous Metals and Processing Technology,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学航空结构件成形制造与装备安徽省重点实验室,合肥230009 [2]合肥中南光电有限公司,合肥231600 [3]合肥工业大学有色金属与加工技术国家地方联合工程研究中心,合肥230009

出　　处：《中国有色金属学报》2021年第9期2403-2411,共9页The Chinese Journal of Nonferrous Metals

基　　金：安徽省博士后研究人员科研活动经费资助项目(2020A391);国家自然科学基金资助项目(51605128);安徽省科技重大专项(JZ2019AKKZ0268)。

摘　　要：采用金属模熔铸工艺制备含0.2%Sc(质量分数)的Al-Zn-Mg-Cu-Sc-Zr合金,分别研究合金铸态下和4种均匀化热处理工艺下的组织转变与元素分布。结果表明:加入0.2%的钪有助于抑制枝晶偏析,消除非平衡共晶组织,得到晶粒尺寸为55~80μm(占整体75%)的合金;铸态组织晶界处分布有大量T(AlZnMgCu)相,在465℃下保温24 h后,T相完全转化为S(Al_(2)CuMg)相;温度提高到480℃后,随着时间延长至24 h,晶界处的S相消失,只有少量的杂质相(Al7Cu2Fe)残留;在经过双级均匀化处理后,平均晶粒尺寸减小到40μm,合金内部析出大量弥散分布的尺寸约为40 nm的L12型Al3Sc相,与α(Al)基体保持完全共格,有效阻碍了晶粒的粗化。In this paper,the structure transformation and element distribution of Al-Zn-Mg-Cu-Zr alloy with 0.2%Sc(mass fraction)in different states were studied.The results show that the addition of 0.2%Sc can help suppress dendrite segregation and eliminate the non-equilibrium eutectic structure,then an alloy with a grain size of 55−80μm(accounting for 75%of the total)is obtained.A large number of T(AlZnMgCu)phases are distributed at the grain boundaries of the as-cast structure.After being kept at 465℃for 24 h,the T phase is completely transformed into S(Al_(2)CuMg)phase.Holding at 465℃for 24 h,the S phase disappears at the grain boundary and only a small amount of impurity phase(Al7Cu2Fe)remains.Through the two-stage homogenization treatment,the average grain size is reduced to 40μm.A large amount of L12-type Al3Sc phases with the sizes of about 40 nm are dispersed inside the alloy,which are completely coherent with theα(Al)matrix and effectively hinder the coarsening of grains.

关 键 词：Al-Zn-Mg-Cu-Sc-Zr合金 均匀化 相转变 Al_(3)Sc 

分 类 号：TG166.3[金属学及工艺—热处理]