Positron annihilation study of the Mg-Zn -Y alloys with long period stacking ordered (LPSO) structures

16th International Conference on Positron Annihilation

Xu, H.X.^1,2,4 ; Inoue, K.^2 ; Nagai, Y.^2 ; Toyama, T.^2 ; Matsukawa, Y.^2 ; Kuramoto, A.^2 ; Egusa, D.^3 ; Abe, E.^3 ; Ye, B.J.^1,4

State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026, China^1

Oarai Center, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313, Japan^2

Department of Materials Engineering, University of Tokyo, Tokyo 113-8656, Japan^3

Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China^4

关键词: Atom-probe tomography;    Coincidence doppler broadening;    First-principles calculation;    Longperiod stacking ordered structure (LPSO);    Low-temperature measurements;    Positron annihilation lifetimes;    Positron lifetime;    Positron trapping;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/443/1/012029/pdf
DOI  :  10.1088/1742-6596/443/1/012029

来源: IOP

【 摘 要 】

The Mg-Zn-Y alloys with long period stacking ordered (LPSO) structures have been studied by positron annihilation lifetime (PAL), coincidence Doppler broadening (CDB) and atom probe tomography (APT). The positron lifetime for all the Mg-Zn-Y alloys is in a range of 221∼225 ps, very close to the positron lifetime for pure Mg bulk, 222 ps. Low temperature measurements of the positron lifetime also give no evidence for shallow positron trapping sites in the LPSO phases. The CDB shows that most of the positrons are annihilated with electrons of Mg. These results suggest that sub-nano scale open volumes, which were expected to exist in the Zn/Y enriched layers synchronized with stacking faults of the LPSO phases by the first principles calculations, are not present.