Metastable Al-Fe intermetallic stabilised by epitaxial relationship

D. Dubaux , E. Gaudry , M.-C. de Weerd , S. Šturm , M. Podlogar , J. Ghanbaja , S. Migot , V. Fournée , Muriel Sicot (1) , J. Ledieu

1 IJL - Institut Jean Lamour

We report the adsorption of Fe for several dosing conditions on Al(1 0 0) surface held at different temperatures. For 2 monolayer equivalent of Fe deposited on the substrate held at 593 K, we observe two rotational domains of a (× 5 5)R26.6°structure by low energy electron diffraction and scanning tunneling microscopy. We identify this structure as the formation of the metastable Al 9 Fe 2 intermetallic phase. The segregation energy and the structural stability of this intermetallic has been analysed using density functional theory based calculations. We propose that the formation of the Al 9 Fe 2 (0 0 1) metastable phase at the expense of other thermodynamically stable Al-Fe compounds, relies on a specific structural similarity between pure Al (0 0 1) planes of the inter-metallic and Al(1 0 0) layers. These 'common' planes lead to the epitaxial relationship (1 0 0) Al [0 0 1] Al ∥ (0 0 1) Al Fe 9 2 [1 3 0] Al Fe 9 2. The Al 9 Fe 2-Al matrix interface is sharp as revealed by transmission electron microscopy measurements.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

D. Dubaux, E. Gaudry, M.-C. de Weerd, S. Šturm, M. Podlogar, et al.. Metastable Al-Fe intermetallic stabilised by epitaxial relationship. Applied Surface Science, 2020, 533, pp.147492. ⟨10.1016/j.apsusc.2020.147492⟩. ⟨hal-02990393⟩