About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
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Symposium
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Development of Light Weight Alloys and Composites
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Presentation Title |
Precipitation of Stable Icosahedral Quasicrystalline Phase in Mg-Al-Zn Alloys |
Author(s) |
Alok Singh, Takanobu Hiroto, Machiko Ode, Karel Tesar, Hidetoshi Somekawa, Toru Hara |
On-Site Speaker (Planned) |
Alok Singh |
Abstract Scope |
Precipitation of stable icosahedral quasicrystalline (i-) phase in a ZA63 Mg-Zn-Al alloy has been discovered, possibly for the first time involving a stable i-phase. It is shown that the stable i-phase forms during solidification of ZA63 alloy. It reversibly transforms to liquid at eutectic temperature near 350°C during heating and cooling. Calculation of phase diagram showed a solvus boundary involving i-phase at the Mg-end. The i-phase goes into solution on prolonged heating/annealing, whereby cooling below 300°C causes precipitation of the i-phase. The precipitates are sharply faceted and show definite orientation relationships with the matrix. Nucleation and transformation characteristics as well as formation of interfaces have been studied using DSC, in-situ XRD and TEM. The findings will be presented and discussed. This discovery opens doors to new studies, such as exploring properties effected by volume fraction of i-phase and its interfaces in a periodic crystal matrix. |