Microstructural, electronic, and mechanical properties of L12 ordered Al3Er and Al3Yb intermetallics: an experimental and first-principles calculations

Abstract

The microstructural, electronic, and mechanical properties of L12 ordered Al3Er and Al3Yb intermetallics were analyzed by x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and first-principles calculations based on the density functional theory (DFT). The results show that the Al3Er intermetallic presents short rod-like structures in the Al-10 wt% Er alloy while the Al3Yb intermetallic presents continuous network structures in the Al-10 wt% Yb alloy. The calculated lattice constants are highly consistent with available experimental measurements, with a deviation less than 1.9%. The results of negative cohesive energy () of the Al3Er and Al3Yb intermetallics indicate that they are both stable structures, while the structural stability of Al3Er intermetallic is stronger than that of Al3Yb. Further analysis on the bonding of electronic structures shows that Al3Er intermetallic is a higher stable structure than Al3Yb. It is found that Al3Er and Al3Yb intermetallics are brittle and the plasticity of Al3Yb intermetallic is stronger than Al3Er. From the results of the Young’s modulus, the Al3Er and Al3Yb intermetallics have strong anisotropic characteristics but the difference between Al3Er and Al3Yb intermetallics is small. According to the calculated Debye temperature, the Al3Er intermetallic exhibits relatively higher thermal conductivity and stronger covalent bonds.