2022-Sustainable Industrial Processing Summit
SIPS2022 Volume 9 Mizutani Intl. Symp. Science of Intelligent & Advanced Materials (SISAM) and Quasi-crystals
| Editors: | F. Kongoli, J. Dubois, E. Gaudry, T. Homma, V. Fournee |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2022 |
| Pages: | 116 pages |
| ISBN: | 978-1-989820-50-6(CD) |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Complex LPSO-type Mg alloys – a unique cluster-induced stabilization
Eiji Abe1;1UNIVERSITY OF TOKYO, Tokyo, Japan;
Type of Paper: Invited
Id Paper: 435
Topic: 42
Abstract:
Recent successful alloy-design showed that Mg alloys with addition of a small amount of Zn and Y (or rare-earth elements) reveal excellent mechanical properties including remarkably improved strength with a reasonable ductility [1]. One of the prominent microstructural features, which are believed to contribute for these excellent properties, is formation of a novel type of long-period structures [2-6]. The structures are fundamentally long-period stacking derivatives of a hexagonal close-packed structure (hcp-Mg), and the resultant stacking polytypes accompany a unique chemical order that occurs to synchronize with the corresponding stacking order; i.e., the synchronized long-period stacking/order (LPSO) structure [3, 6]. We have attempted to evaluate phase stability [7] as well as to construct model structures of the complex LPSO crystals, based on electron microscopy observations and first-principles calculations [4]. Structural characteristics are well represented by the TM6RE8 clusters with a L12-type short-range order (SRO) configuration, embedded in the local fcc-Mg layer of the LPSO [4, 5]. Interestingly, it turns out that the local electronic structures as well as relaxation behaviors of the SRO clusters significantly contribute to a phase stability. In the talk, I will describe a unique SRO cluster-induced phase stabilization, providing an important clue that leads to a universal concept on how we choose proper elements during alloy design.
Keywords:
Alloys; Atomic structures; Computational simulation; Electronic structures;References:
[1] Y. Kawamura, M. Yamasaki, Mater. Trans. 48 (2007) 2986.[2] E. Abe et al., Acta Mater. 50 (2002) 3845.
[3] E. Abe et al., Philos. Mag. Lett. 91 (2011) 690.
[4] D. Egusa, E. Abe, Acta Mater. 60 (2012) 166.
[5] K. Yamashita et al., J. Alloys and Compounds 788 (2019) 277-282.
[6] K. Guan et al., Scripta Mater. 207 (2022) 114282.
[7] M. Egami et al., Materials and Design 188 (2020) 108452.