TY - JOUR
T1 - Role of substituted atoms in stacking fault formation in long-period stacking ordered system
AU - Kawano, S.
AU - Iikubo, S.
AU - Ohtani, H.
N1 - Funding Information:
We are grateful to Prof. M. Matsushita for helpful discussions about the experiments. This work was supported by the MEXT KAKENHI Grant Number 23109005 . This work was also performed under the Cooperative Research Program of “Network Joint Research Center for Materials and Devices”.
Funding Information:
We are grateful to Prof. M. Matsushita for helpful discussions about the experiments. This work was supported by the MEXT KAKENHI Grant Number 23109005. This work was also performed under the Cooperative Research Program of ?Network Joint Research Center for Materials and Devices?.
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2020/1
Y1 - 2020/1
N2 - To study the formation mechanism of the long-period stacking ordered (LPSO) structures, the reaction pathways of solid–solid transformations from a hexagonal close-packed (HCP) structure to LPSO structures in Mg-Y-Zn alloys were calculated using the generalized solid-state nudged elastic band method. The energy increases along the transition from HCP to 18R, and the peak positions represent the activation energy for the transition. Y substitution hardly changes the activation energy but makes the 18R-type LPSO structure more stable than HCP. In contrast, Zn or Y + Zn substitution results in higher activation energy and makes the 18R-type LPSO structure less stable than HCP. The calculated results for 14H and 24R LPSO structures also show similar activation energy and LPSO stability to the HCP-18R transition. Therefore, Y substitution plays an important role in stabilizing the stacking faults in LPSO systems. For the microscopic mechanism, the volume dependence of the total energy in pure FCC and HCP Y were examined, and the result suggests that FCC-Y is stable than HCP-Y under pressure. Therefore, the effect of substitution of Y in HCP Mg can be explained by the characteristics of Y under the chemical pressure exerted by the small size of Mg lattice.
AB - To study the formation mechanism of the long-period stacking ordered (LPSO) structures, the reaction pathways of solid–solid transformations from a hexagonal close-packed (HCP) structure to LPSO structures in Mg-Y-Zn alloys were calculated using the generalized solid-state nudged elastic band method. The energy increases along the transition from HCP to 18R, and the peak positions represent the activation energy for the transition. Y substitution hardly changes the activation energy but makes the 18R-type LPSO structure more stable than HCP. In contrast, Zn or Y + Zn substitution results in higher activation energy and makes the 18R-type LPSO structure less stable than HCP. The calculated results for 14H and 24R LPSO structures also show similar activation energy and LPSO stability to the HCP-18R transition. Therefore, Y substitution plays an important role in stabilizing the stacking faults in LPSO systems. For the microscopic mechanism, the volume dependence of the total energy in pure FCC and HCP Y were examined, and the result suggests that FCC-Y is stable than HCP-Y under pressure. Therefore, the effect of substitution of Y in HCP Mg can be explained by the characteristics of Y under the chemical pressure exerted by the small size of Mg lattice.
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U2 - 10.1016/j.commatsci.2019.109210
DO - 10.1016/j.commatsci.2019.109210
M3 - Article
AN - SCOPUS:85071570033
SN - 0927-0256
VL - 171
JO - Computational Materials Science
JF - Computational Materials Science
M1 - 109210
ER -