Improved Properties in Relation to Fine Precipitate Microstructures Tailored by Combinatorial Processes in an Al-Cu-Mg-Si Alloy  

作　　者：Fengjiao Niu Jianghua Chen Cuilan Wu Jing Wu Xiandong Xu Pan Xie Xiongwei Yu 

机构地区：[1]Center for High-Resolution Electron Microscopy,College of Materials Science and Engineering,Hunan University,Changsha 410082,China

出　　处：《Acta Metallurgica Sinica(English Letters)》2020年第11期1527-1534,共8页金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.51671082,51831004,11427806,51801060,51471067);the National Key Research and Development Program of China(No.2016YFB0300801)。

摘　　要：The 2xxx series Al alloys have been widely used in aerospace industry owing to their high strength,good plasticity and superior formability.To ensure a good control of shape,the quenched alloy sheets require a small pre-deformation before artificial aging.However,this pre-deformation considerably deteriorates the mechanical strength of the Al-3.0 Cu-1.8 Mg-0.5 Si(wt%)alloys due to the formation of unfavorable large-sized precipitates at dislocations.To tackle this issue,we designed a pre-aging process prior to the pre-deformation.The thermal-mechanical treatment,involving pre-aging,pre-deformation and subsequent aging,markedly enhanced the ultimate tensile strength up to 521 MPa compared to that(448 MPa)of the alloy without pre-aging.Microstructure characterization revealed that the fine precipitates(~2 nm)with a uniform dispersion were promoted within the Al matrix,which in turn partly suppressed the formation of the unfavorable large-sized precipitate(~100 nm).Our findings provide a new clue for designing stronger Al alloys with age-hardenability.

关 键 词：Aluminum alloys Thermo-mechanical treatment Precipitation Age-hardenability 

分 类 号：TG146.21[一般工业技术—材料科学与工程]