Effects in Mg-Zn-based alloys strengthened by quasicrystalline phase

The International Workshop on Positron Studies of Defects 2014

Vlek, M.^1 ; iek, J.^1 ; Luká, F.^1 ; Melikhova, O.^1 ; Hruka, P.^1 ; Procházka, I.^1 ; Vlach, M.^1 ; Stuliková, I.^1 ; Smola, B.^1 ; Jager, A.^2

Charles University in Prague, Faculty of Mathematics and Physics, V Holeovikách 2, Praha 8

18000, Czech Republic^1

Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, Praha 8

18221, Czech Republic^2

关键词: Biomedical applications;    Icosahedral phase;    In-situ synchrotrons;    Lightweight structural materials;    Positron lifetime spectroscopy;    Precipitation effects;    Quasi-crystalline structure;    Quasicrystalline phase;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/674/1/012005/pdf
DOI  :  10.1088/1742-6596/674/1/012005

来源: IOP

【 摘 要 】

Magnesium Mg-based alloys are promising lightweight structural materials for automotive, aerospace and biomedical applications. Recently Mg-Zn-Y system attracted a great attention due to a stable icosahedral phase (I-phase) with quasicrystalline structure which is formed in these alloys. Positron lifetime spectroscopy and in situ synchrotron X-ray diffraction were used to study thermal stability of I-phase and precipitation effects in Mg-Zn-Y and Mg- Zn-Al alloys. All alloys containing quasicrystalline I-phase exhibit misfit defects characterized by positron lifetime of ∼ 300 ps. These defects are associated with the interfaces between I- phase particles and Mg matrix. The quasicrystalline I-phase particles were found to be stable up to temperatures as high as ∼ 370°C. The W-phase is more stable and melts at ∼ 420°C. Concentration of defects associated with I-phase decreases after annealing at temperatures above ∼ 300°C.