Metallurgical Abstracts on Light Metals and Alloys vol.55
Effect of grain boundary characters on local deformation behavior in Al-Mg-Si alloy
Takuya Hashimoto*, Ken-ichi Ikeda** and Seiji Miura**
*Division of Materials Science and Engineering, Graduate School of Engineering, Hokkaido University
**Division of Materials Science and Engineering, Faculty of Engineering, Hokkaido University
[Published in J. Japan Inst. Met. Mater. Vol. 85, No. 1 (2021), pp. 7–16]
https://www.jstage.jst.go.jp/article/jinstmet/85/1/85_JD202002/_article/-char/en
E-mail: ikeda.ken-ichi[at]eng.hokudai.ac.jp
Key Words: Al-Mg-Si alloy, Age-hardening, Precipitate free zone, Nanoindentation, Grain boundary character
To clarify the effect of the grain boundary (GB) of the Al-Mg-Si alloy on the aging precipitation behavior and the mechanical properties, nanoindentation tests were conducted near the GB. After obtaining the GB characters by electron back-scattered diffraction (EBSD) analysis and nanoindentation tests were carried out on under-aged, peak-aged, and over-aged samples. And then, the indentation areas were observed by back-scattered electrons imaging (BSE) in order to identify indentation positions to the GB. In this study, focusing on the rotation angle, the high-angle GB (HAGB) and the low-angle GB (LAGB) were selected for the GB character. In addition, coincidence site lattice GBs (CSL) were selected as the special GB. In the 180°C under-aged sample, the nano-hardness near GB is higher than that far from GB, while 180℃ peak-aged and 250°C aged samples, the nano-hardness is lower than that far from GB. Then the amount of change in hardness of HAGB was larger than that of the LAGB. This suggests that the GB character affects the aging precipitation behavior and mechanical properties.
Nano-hardness around grain boundaries at aging temperature of 180°C ; (a) at under-aged around HAGB, (b) at peak-aged around HAGB, (c) at under-aged around LAGB, (d) at peak-aged around LAGB.