The effect of grain boundary character evolution on the intergranular corrosion behavior of advanced Al-Mg-3wt%Zn alloy with Mg variation

Journal Article · Sat Dec 15 04:00:00 EST 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2018.09.044· OSTI ID:23118112

Ding, Qingwei; Zhang, Di; Zuo, Jinrong; Hou, Shengli ^[1]; Zhuang, Linzhong ^[1]; Zhang, Jishan ^[1]

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1. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

Highlights: • The relationship among GBCD, GBPs, IGC behavior and Mg content in the age hardenable Al-Mg-3.0wt%Zn alloy is established. • None of grain boundaries are found to be immune to the GBPs. • GBPs along low angle grain boundaries are more discontinuous than high angle grain boundaries. • The IGC mechanism of Al-Mg-3.0wt%Zn alloy is clarified. • A new method for the statistical analysis of the continuity of GBPs is used in this paper. The characteristics of grain boundary and grain boundary precipitates of Al-Mg-3wt%Zn alloy with different Mg contents were systematically investigated. Observation by optical microscopy, transmission electron microscopy, scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy show that the morphology and composition of the grain boundary precipitates change little with the variation in the Mg content. Based on the statistical analysis of the spacings between two adjacent grain boundary precipitates, we find that the decrease in the Mg content reduces the continuity of the grain boundary precipitates. Comparing this result with the electron backscattered diffraction analysis, it can be concluded that the continuity of grain boundary precipitates is affected by the proportion of low angle grain boundaries. The observations of grain boundary precipitates at both low angle grain boundaries and high angle grain boundaries using transmission electron microscopy indicate that low angle grain boundaries have more discontinuous grain boundary precipitates. Combining these results with the results of the intergranular corrosion test, the microscopic features of this corrosion behavior and corrosion mechanism are revealed.

• OSTI ID: 23118112
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 146; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
BACKSCATTERING
ELECTRON DIFFRACTION
GRAIN BOUNDARIES
INTERGRANULAR CORROSION
MORPHOLOGY
OPTICAL MICROSCOPY
PRECIPITATION
TRANSMISSION ELECTRON MICROSCOPY
X-RAY SPECTROSCOPY