Hydrogen-induced failure in a partially-recrystallized Al-Zn-Mg-Cu alloy with different aging conditions: Influence of deformation behavior dominated by microstructures

• Published in: Materials & design Vol. 233; p. 112199
• Main Authors: Chen, Mingyang, Liu, Shengdan, He, Kezhun, Zheng, Xu, Zhang, Yong, Tang, Jianguo, Ye, Lingying
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2023; Elsevier
• Subjects: Al-Zn-Mg-Cu alloy; Deformation behavior; Hydrogen embrittlement; Microstructure; Microstructure; Deformation behavior; Hydrogen embrittlement; Al-Zn-Mg-Cu alloy
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2023.112199

[Display omitted] •Naturally-aged and peak-aged samples with shearing deformation are prone to hydrogen embrittlement.•Over-aged sample with bypassing deformation is hardly affected by hydrogen environment.•The grain boundary of recrystallized grains is prone to intergranular cracking.•Transgranular cracking tends to appear in the interior of unrecrystallized grains.•The cracking mode is the same in silicone oil and in-situ hydrogen charging environments. Hydrogen-induced failure in a partially-recrystallized Al-Zn-Mg-Cu alloy with different aging conditions was studied by in-situ electrochemical hydrogen charging method, and the hydrogen-induced cracking mechanism was elucidated by investigating the microstructure-dominated deformation behavior. It was found that in naturally-aged and peak-aged samples, cracks initiate at sample surfaces, and deformation dominated by shearing facilitates hydrogen diffusion, resulting in a high hydrogen embrittlement susceptibility. However, in the over-aged sample, deformation dominated by bypassing cannot transport hydrogen efficiently, which exerts no effect on crack initiation at the sample center. In addition, the same cracking pattern exists on all samples in silicone oil and in-situ hydrogen charging environments. The grain boundary of recrystallized grains is prone to strain localization, leading to intergranular cracking. In unrecrystallized grains, transgranular cracks propagate along intersections of slip lines and subgrain boundaries. This study improves the understanding of hydrogen embrittlement in new generation Al-Zn-Mg-Cu alloy by linking the existing hydrogen embrittlement mechanism to the deformation behavior dominated by microstructures.