Experimental and theoretical electronic distributions in Al-Cu-based alloys

Abstract

We report on experimental and calculated occupied and unoccupied electronic distributions of crystalline A12Cu and various Al-Cu-Fe alloys. The experiments have been carried out by means of soft-x-rayspectroscopy and photoelectron-spectroscopy techniques. The densities of states have been calculated using either the linear-muffin-tin-orbital atomic-sphere-approximation or the augmented-plane-wave methods. The comparison between experiment and calculations is discussed. We pay special attention to the effect of Fe in the various alloys and emphasize the role of Al atom neighbors. We propose that changes in Al site occupancy that induce changes in Al p-d hybridization near the Fermi level could be responsible for the modifications of the densities of states observed in quasicrystalline Al-Cu-Fe phases with respect to the crystalline Al-Cu2Fe alloy.

Electronic structure of quasicrystalline compounds

“…The authors assigned the qualitative difference between these results and the previous data to the small number of k points involved in the earlier calculations. On the other hand, calculations performed for usual intermetallics close to quasicrystals or very low order approximants did not display such numerous narrow spikes [11][12][13][14]. It is also important to note that up to date no experiment revealed the spiky structure of the DOS predicted theoretically, whatever the technique and the resolution of the measurement [15][16][17].…”

Friction and solid-solid adhesion on complex metallic alloys

“…To this end, we refer to the computed DOS obtained for the ω compound of composition Al 70 Cu 20 Fe 10 and tetragonal structure (P4/mnc; a = 0.6336 nm; c = 1.4870 nm) [43]. Ab initio computation of the DOS was based on the linear muffin-tin orbital (LMTO) method in the augmented plane wave approximation, see [43] for details.…”

Structurally complex metallic coatings in the Al-Cu system and their orientation relationships with an icosahedral quasicrystal

“…[1][2][3][4][5][6][7][8][9][10] This was motivated in part by the possibility of developing CMAs as new coating materials with low friction, reduced adhesion, and good corrosion resistance for technological applications. [11][12][13] Those surface properties are related to the peculiar electronic structure of CMAs characterized by a pseudogap at the Fermi level, usually associated with poor metallic behavior.…”