First-principles Calculations of Bulk and Interfacial Thermodynamic Properties of the T1 phase in Al-Cu-Li alloys

초록

We recently proposed a new, low-energy atomic structure of the Al2CuLi (T-1) phase using first-principles calculations based on density functional theory [Acta Mater. 145 (2018) 337-346]. Here, we refine the Li positions in the proposed T-1 structure and find that the T-1 phase has a tie-line with Al at finite-temperature by vibrational entropic stabilization on the Gibbs triangle of the ternary Al-Cu-Li system. We also derive a low-energy T-1/Al coherent interfacial structure and find that Ag and Mg solutes are predicted to segregate to the coherent interface, which is in agreement with recent experimental observations by atom probe tomography. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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