کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5436225 | 1509547 | 2017 | 10 صفحه PDF | دانلود رایگان |

The low-temperature phase of η-Fe2Al5 has been identified experimentally for the first time and the crystal structure of the low-temperature phase (designated as ηâ²) has been refined by scanning transmission electron microscopy, combined with first-principles calculations. The low-temperature ηⲠphase has a tripled superlattice structure based on the orthorhombic η-Fe2Al5 (space group Cmcm), in which Al atoms occupy two ninths of the partially occupied Al sites (Al2 and Al3) in a chain along the c-axis of the orthorhombic parent lattice in an ordered manner, giving rise to the monoclinic space group C2/c, the stoichiometric composition Fe3Al8 (Al-27.3 at.%Fe), and the Pearson symbol mC44. The partially occupied Al sites along the c-axis of the orthorhombic parent lattice are converted to the Al site (Al3â³ site) of full occupancy in the monoclinic superlattice of the ηâ²-Fe3Al8. The η-ηⲠphase transformation temperature decreases from between 350 and 400 °C at the composition of Al-26.7 at.%Fe to between 300 and 350 °C at compositions in the range of Al-27.3 to 28.6 at.%Fe, indicating that the ηⲠphase exists primarily at the Fe-lean side of the solid-solubility region of the η-Fe2Al5 phase.
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Journal: Acta Materialia - Volume 129, 1 May 2017, Pages 290-299