Improving the strength and SCC resistance of an Al-5Mg-3Zn alloy with low-angle grain boundary structure  

作　　者：Z.C.Tang W.Xu D.Y.Zhao B.Zhang 

机构地区：[1]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [2]School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China

出　　处：《Journal of Materials Science & Technology》2023年第30期63-73,共11页材料科学技术（英文版）

基　　金：This research was financially supported by the National Nat-ural Science Foundation of China(Grant No.52171088);the Young Elite Scientists Sponsorship Program by CAST(grant No.2022QNRC001).We thank X.Si for assistance in sample prepara-tion.

摘　　要：The strength of traditional Al-Mg alloys is relatively low because it mainly relies on solid solution strengthening.Adding a third component to form precipitation can improve their strength,but it usually leads to high-stress corrosion cracking(SCC)sensitivity due to the formation of high-density precipitates at grain boundaries(GBs).So far,it is still challenging to improve the strength of Al-Mg alloys without re-ducing SCC resistance.Herein,a nanostructured Al-5Mg-3 Zn alloy with a good yield strength of 336 MPa and good elongation was successfully produced.By dynamic plastic deformation and appropriate anneal-ing treatment,near-equiaxed nanograins were introduced in the nanostructured Al-5Mg-3 Zn alloy with a high proportion(71%)of the low-angle grain boundary.TEM statistical investigations show that the pre-cipitation of active T’phase at GBs has been greatly suppressed in the nanostructured Al-5Mg-3 Zn alloy at sensitized conditions,and the area fraction of GB precipitates is reduced from 72%to 21%,which sig-nificantly decreases the SCC susceptibility.This study provides guidance for developing advanced Al-Mg alloy with high SCC resistance.

关 键 词：Al-5Mg-3 Zn alloy Stress corrosion cracking Low angle grain boundary Nanostructured Dynamic plastic deformation 

分 类 号：TG1[金属学及工艺—金属学]