TY - JOUR
T1 - First-principles study of hydrogen segregation at the MgZn2 precipitate in Al-Mg-Zn alloys
AU - Tsuru, T.
AU - Yamaguchi, M.
AU - Ebihara, K.
AU - Itakura, M.
AU - Shiihara, Y.
AU - Matsuda, K.
AU - Toda, H.
N1 - Funding Information:
This work was supported by a JST Collaborative Research Based on Industrial Demand “Heterogeneous Structure Control: Towards Innovative Development of Metallic Structural Materials.” The simulations presented in this work were performed on JAEA ICE X system. T.T acknowledges the financial support of Grant-in-Aid for Scientific Research (C) (No. 16K06714).
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/6/1
Y1 - 2018/6/1
N2 - Hydrogen embrittlement susceptibility of high strength 7xxx series Al alloys has been recognized as the critical issues in the practical use of Al alloys. In spite of the recent improvement of experimental technique, the hydrogen distribution in Al alloys is still unclear. Focusing on the interface between MgZn2 precipitates and an Al matrix, which is considered as one of the important segregation sites in these alloys, we investigated the stable η-MgZn2–Al interface, and the possible hydrogen trap sites in MgZn2 and at the η-MgZn2–Al interface via first-principles calculation. Most of the interstitial sites inside the MgZn2 crystal were not possible trap sites because their energy is relatively higher than that of other trap sites. The trap energy of the most favorable site at the η-MgZn2–Al is approximately −0.3 eV/H, which is more stable that of the interstitial site at the grain boundary. The interface between MgZn2 and Al is likely to be a possible trap site in Al alloys. Moreover, hydrogen atoms do not tend to be trapped around Zn, but a trap site around Mg is favorable; this observation is consistent with previous experimental observations.
AB - Hydrogen embrittlement susceptibility of high strength 7xxx series Al alloys has been recognized as the critical issues in the practical use of Al alloys. In spite of the recent improvement of experimental technique, the hydrogen distribution in Al alloys is still unclear. Focusing on the interface between MgZn2 precipitates and an Al matrix, which is considered as one of the important segregation sites in these alloys, we investigated the stable η-MgZn2–Al interface, and the possible hydrogen trap sites in MgZn2 and at the η-MgZn2–Al interface via first-principles calculation. Most of the interstitial sites inside the MgZn2 crystal were not possible trap sites because their energy is relatively higher than that of other trap sites. The trap energy of the most favorable site at the η-MgZn2–Al is approximately −0.3 eV/H, which is more stable that of the interstitial site at the grain boundary. The interface between MgZn2 and Al is likely to be a possible trap site in Al alloys. Moreover, hydrogen atoms do not tend to be trapped around Zn, but a trap site around Mg is favorable; this observation is consistent with previous experimental observations.
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U2 - 10.1016/j.commatsci.2018.03.009
DO - 10.1016/j.commatsci.2018.03.009
M3 - Article
AN - SCOPUS:85043279504
SN - 0927-0256
VL - 148
SP - 301
EP - 306
JO - Computational Materials Science
JF - Computational Materials Science
ER -