Povzetek
This 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.
Ključne besede
Al-Cr-Sc system;Laves phase;crystal structure refinement;HAADF-STEM;
Podatki
Jezik: |
Angleški jezik |
Leto izida: |
2021 |
Tipologija: |
1.01 - Izvirni znanstveni članek |
Organizacija: |
UL NTF - Naravoslovnotehniška fakulteta |
UDK: |
669 |
COBISS: |
88540675
|
ISSN: |
2073-4352 |
Št. ogledov: |
98 |
Št. prenosov: |
45 |
Ocena: |
0 (0 glasov) |
Metapodatki: |
|
Ostali podatki
Vrsta dela (COBISS): |
Članek v reviji |
Strani: |
1535-1-1535-18 |
Letnik: |
ǂVol. ǂ11 |
Zvezek: |
ǂiss. ǂ12 |
Čas izdaje: |
2021 |
DOI: |
10.3390/cryst11121535 |
ID: |
15297835 |