Effect of pre-strain on precipitation and exfoliation corrosion resistance in an Al-Zn-Mg alloy

1st International Conference on Frontiers of Materials Synthesis and Processing

材料科学;化学

Lu, Xianghan^1 ; Du, Zhiwei^2 ; Han, Xiaolei^2 ; Li, Ting^2 ; Wang, Guojun^3 ; Lu, Liying^3 ; Bai, Xiaoxia^3 ; Zhou, Tietao^1

School of Materials Science and Engineering, Beihang University, Beijing

100191, China^1

National Analysis and Testing Center for Nonferrous Metals and Electronic Materials, Beijing General Research Institute for Nonferrous Metals, Beijing

100088, China^2

Northeast Light Alloy Co. Ltd., Harbin

150060, China^3

关键词: Al-Zn-Mg alloy;    Corrosion behavior;    Coverage ratio;    Electrical conductivity;    High angle grain boundaries;    Scanning transmission electron microscopy;    Select area electron diffractions;    Supersaturated solid solution (sss);   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/274/1/012007/pdf
DOI  :  10.1088/1757-899X/274/1/012007

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

To investigate the effect of pre-strain on behaviors in a specially developed Al-4.5Zn-1.2Mg alloy, transmission electron microscopy (TEM) bright field (BF) imaging combined with select area electron diffraction (SAED), Vickers-hardness tests and electrical conductivity tests was conducted for insight into precipitation in aluminum (Al) matrix during two step ageing, and standard exfoliation corrosion (EXCO) test combined with high-angle angular dark field scanning transmission electron microscopy (HAADF-STEM) and scanning electron microscopy (SEM) was carried out for corrosion behavior. Results showed that pre-strain accelerated precipitation during two step ageing as the sequence of: (i) supersaturated solid solution (SSS), GPI zones precipitations, GPI dissolution; (ii) SSS, fcc precipitates, η' phases or η phases. And the precipitation hardening of the fcc precipitates was not effective as GPI zones. Pre-strain also accelerated EXCO developing, which was mainly attributed to the coverage ratio of η phases on high-angle grain boundaries (HAGBs) increasing as pre-strain increase.