Local structure analysis of long-period stacking ordered (LPSO) structure phase-containing Mg alloys by X-ray absorption spectroscopy*

Long-period stacking (LPSO) type Mg alloy [1] has the structure modulation and concentration modulation of the atomic arrangement in long period, and is different from the hcp structure which is a pure Mg crystal structure. In LPSO-Mg alloy, kinks are formed due to the introduction of a significant difference in grain orientation in the crystal accompanying plastic deformation, which leads to material strengthening. However, the mechanism of kink formation and its strengthening has not yet been clarified. In this study, the changes in the local structure of solid solution atoms during the formation of LPSO-phase and the kink deformation were investigated by x-ray absorption spectroscopy. As a result, the central atom of L1₂ cluster of LPSO-phase contained in Mg alloy was identified, and the possibility of re-diffusion of solid solution atoms by kink deformation was suggested.
[1] Y. Kawamura, et al., Mater. Trans., 42, 1172 (2001).