Crystal structure, microstructure and electronic properties of a newly discovered ternary phase in the Al-Cr-Sc systemKušter, Monika (Avtor) Meden, Anton (Avtor) Markoli, Boštjan (Avtor) Samardžija, Zoran (Avtor) Vončina, Maja (Avtor) Boulet, Pascal (Avtor) Gaudry, Émilie (Avtor) Dubois, Jean-Marie (Avtor) Šturm, Sašo (Avtor) Al-Cr-Sc systemLaves phasecrystal structure refinementHAADF-STEMThis study focused on the crystal and electronic structures of a newly discovered phase in the Al-Cr-Sc system. The latter two species do not mix in a binary alloy, but can be alloyed with aluminium in the vicinity of the Al$_{2−x}$Cr$_x$Sc composition, where 0.3 < x < 0.5. After preparation of the pure constituents via arc melting, high-temperature annealing at 990 °C for 240 h was required to achieve full mixing of the elements. A detailed characterisation of the crystal structure, alloy microstructure and stability was obtained using single-crystal X-ray diffraction (SCXRD) and powder X-ray diffraction (PXRD), in addition to transmission electron microscopy (TEM), especially in highangle annular dark-field scanning transmission electron microscopy (HAADF-STEM) mode, scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDXS) and differential scanning calorimetry (DSC) measurements. The crystal structure was refined to a hexagonal unit cell of the MgZn$_2$ type, space group no. 194, P6$_3$/mmc, which belongs to the Laves phases family. Special attention was paid to the occupancy of the crystallographic sites that were filled by both Cr and Al atoms. First-principles calculations based on the density functional theory (DFT) were performed to investigate the electronic structure of this ternary phase. The total density of states (DOS) exhibited a pronounced sp character, where a shallow pseudo-gap was visible 0.5 eV below the Fermi energy that brought a small but definite contribution to the thermodynamic stability of the compound.20212022-05-12 14:01:37Članek v reviji136638sl