Microstructures and properties evolution of Al-Zn-Mg-Cu alloy under electrical pulse assisted creep aging  

作　　者：Tian-Jun Bian Heng Li Chao Lei Chang-Hui Wu Li-Wen Zhang 

机构地区：[1]State Key Laboratory of Solidification Processing,School of Materials Science and Engineering,Northwestern Polytechnical University,Xi’an,710072,People’s Republic of China [2]School of Materials Science and Engineering,Xi’an University of Technology,Xi’an,710048,People’s Republic of China

出　　处：《Advances in Manufacturing》2022年第4期596-609,共14页先进制造进展（英文版）

基　　金：The research is supported by the Natural Science Foundation of China(Grant Nos.51905424,51522509,51235010)。

摘　　要：Creep aging(CA)is a promising forming technology for integral panels with complex structures.However,how to balance excellent corrosion resistance and strength is still a challenge for CA parts.By synchronously applying electrical pulse(300 Hz,15 A/mm^(2))in the middle of steady-state CA of Al-Zn-Mg-Cu alloy,the electrically assisted CA(ECA)is proposed to induce retrogression rapidly for realizing a three-step aging(retrogression and re-aging,RRA)in CA to tailor the needed properties balance.It is compared with conventional CA with one-step aging(peak aging,T6 or over aging,T7),two-step aging(over aging,T73)and RRA in hardness,intergranular corrosion and microstructures.For the ECA of pre-aging and re-aging for 20 h plus electropulsing for 10 min,the hardness is 10.5%,20.5%and 18.9%higher than those of CA with T6,T7 and T73 processes,respectively,while the corrosion resistance is higher than T6 process and lower than T7 and T73 processes.Although the hardness and corrosion resistance are comparable to those of the CA with the RRA process,ECA takes one hour less due to the accelerated effect of the electropulsing and is not limited by the thick plates.The improved comprehensive performance of the ECA sample is due to both fine intragranular precipitatesη′and large discontinuous grain boundary precipitatesη.

关 键 词：Creep aging(CA) Electrical pulse RETROGRESSION Corrosion HARDNESS Al-Zn-Mg-Cu alloy 

分 类 号：TG14[一般工业技术—材料科学与工程]