Dislocation-Induced Precipitation and Its Strengthening of Al–Cu–Li–Mg Alloys with High Mg  

作　　者：Xiangpeng Gong Shifang Luo Shiyong Li Cuilan Wu 

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)》2021年第5期597-605,共9页金属学报（英文版）

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

摘　　要：Generally, the good combination of pre-deformation and aging can improve the mechanical strength of the Al–Cu–Li–Mg alloys. However, the effects of pre-deformation on competitive precipitation relationship and precipitation strengthening have not been clarified in detail in Al–Cu–Li–Mg alloys with high Mg. In the present study, the effects of pre-deformation level on the microstructure and mechanical properties of an Al–2.95 Cu–1.55 Li–0.57 Mg–0.18 Zr alloy have been investigated. It is found that the introduction of dislocation by 5% pre-deformation can facilitate the precipitation of new successive composite precipitates and T _1 precipitates along the sub-grain boundaries or dislocations and inhibit the precipitation of dispersive GPB zones which is the main precipitates of the alloys without pre-deformation. The introduction of 5% pre-deformation can enhance the mechanical properties considerably. When the pre-deformation level increases from 5 to 15%, the number density of the successive composite precipitates and T _1 precipitates increases, and the aspect ratio of T _1 precipitates decreases. The decrease in T _1 precipitate aspect ratio and the increment of the successive composite precipitates result in the reduction in precipitation strengthening. Therefore, the increase in pre-deformation level from 5 to 15% does not further improve the mechanical properties of the alloys, although the dislocation strengthening increases continuously.

关 键 词：Aluminum alloys Precipitation behavior PRE-DEFORMATION Precipitation strengthening Dislocation strengthening 

分 类 号：TG146.21[一般工业技术—材料科学与工程]